Solving (x+2)^2 - 10 = 25 Quadratic Equation Using Square Root Property

by Kenji Nakamura 72 views

Hey guys! Let's dive into solving a quadratic equation using the square root property. It's a super handy method when you've got a squared term isolated. We'll break down each step, making sure it's crystal clear how to tackle these problems. So, grab your math hats, and let's get started!

Understanding the Square Root Property

The square root property is your best friend when dealing with equations where a squared term is isolated on one side. Essentially, it states that if you have something like x² = a, then x can be either the positive or negative square root of a. Mathematically, we write this as x = ±√a. This "±" symbol is super important because it reminds us that both the positive and negative roots are solutions to the equation. For example, if we have x² = 9, then x can be either 3 or -3 because both 3² and (-3)² equal 9. This property is a direct result of the definition of a square root, which is the value that, when multiplied by itself, gives the original number. Now, why is this property so useful? Well, it allows us to directly "undo" the squaring operation, which is often the key to isolating the variable we're trying to solve for. In more complex quadratic equations, we might need to do some algebraic manipulations to get the equation into a form where we can apply the square root property. This often involves isolating the squared term, which means moving all other terms to the other side of the equation. Once we have the squared term isolated, we can confidently apply the square root property and find our solutions. Remember, the beauty of this method lies in its simplicity and directness. It's a powerful tool in your math arsenal, especially for equations that fit the right form. So, keep practicing, and you'll become a pro at using the square root property to solve quadratic equations!

Step-by-Step Solution

Let's tackle the given equation step-by-step, ensuring we understand each move we make. Our starting point is:

(x + 2)² - 10 = 25

Step 1: Isolate the Squared Term

Our initial goal is to get the squared term, (x + 2)², by itself on one side of the equation. To do this, we need to get rid of the "- 10". The opposite of subtraction is addition, so we'll add 10 to both sides of the equation. This maintains the balance and keeps our equation valid.

(x + 2)² - 10 + 10 = 25 + 10

This simplifies to:

(x + 2)² = 35

Great! We've successfully isolated the squared term. Now we're ready to apply the square root property. This is a crucial step because it sets us up to directly solve for x. Isolating the squared term is like setting the stage for the main act – we've prepped the equation so that the square root property can work its magic. Without this step, we wouldn't be able to easily "undo" the squaring operation. Think of it as peeling away the layers of an onion; we're slowly but surely getting closer to the core, which in this case is the value of x. This careful manipulation is what makes algebra so powerful – we're using the rules of math to transform the equation into a form that's easier to work with. So, always remember, isolating the squared term is the first key step when you're planning to use the square root property.

Step 2: Apply the Square Root Property

Now that we have (x + 2)² = 35, we can use the square root property. This means we take the square root of both sides of the equation. Remember, when we do this, we need to consider both the positive and negative square roots.

√(x + 2)² = ±√35

This simplifies to:

x + 2 = ±√35

The "±" symbol is super important here. It tells us that there are two possible solutions: one where we use the positive square root of 35, and another where we use the negative square root of 35. For many, this is a turning point, as it directly addresses the squared term. By applying the square root property, we've effectively unwrapped the square, revealing the expression inside. This step is like unlocking a door – we're moving from an equation with a squared term to a linear equation that we can solve more easily. This transformation is what makes the square root property such a powerful tool. It allows us to bypass more complex methods, like factoring or using the quadratic formula, in certain situations. The ± symbol, although seemingly small, carries a lot of weight. It's a reminder that quadratic equations often have two solutions, and we need to account for both to get the complete picture. So, embrace the ±, and let it guide you to both solutions of the equation!

Step 3: Isolate x

Our final step is to isolate x to find its value. We have x + 2 = ±√35. To get x by itself, we need to subtract 2 from both sides of the equation.

x + 2 - 2 = -2 ± √35

This gives us:

x = -2 ± √35

This is our solution! It tells us that x can be two different values: -2 + √35 and -2 - √35. These are the exact solutions to the equation. We've successfully navigated through the equation, isolating x and uncovering its possible values. This final step is the culmination of all our hard work, where we transform the equation into a clear statement of what x is equal to. Subtracting 2 from both sides is the final piece of the puzzle, the move that sets x free. Now, we have two solutions, neatly packaged in the form -2 ± √35. These aren't just numbers; they're the specific values that make the original equation true. Think of it as finding the precise coordinates on a map – we've located the exact points that satisfy the conditions of our equation. This feeling of accomplishment is what makes math so rewarding. We've started with a problem, followed a logical path, and arrived at a clear, concise answer. So, celebrate this victory and remember the steps we took, because they'll serve you well in future mathematical adventures!

Final Answer

The solutions to the quadratic equation (x + 2)² - 10 = 25 are:

x = -2 + √35 and x = -2 - √35

These are the exact solutions. If we needed approximate values, we could use a calculator to find the decimal approximations of √35 and then perform the addition and subtraction. But for now, we've nailed the exact solutions, which is a fantastic achievement!

Common Mistakes to Avoid

When solving quadratic equations using the square root property, there are a few common pitfalls to watch out for. Avoiding these mistakes will help you get to the correct solution every time. So, let's shine a spotlight on these potential errors and learn how to steer clear of them.

Forgetting the ± Sign

This is probably the most common mistake. When you take the square root of both sides of an equation, remember that you need to consider both the positive and negative roots. Forgetting the ± sign means you're only finding one solution when there are actually two. This happens because both a positive number and its negative counterpart, when squared, will result in the same positive number. For example, both 3² and (-3)² equal 9. So, if you only consider the positive root, you're missing half the picture. Always double-check that you've included the ± sign when applying the square root property. It's a small symbol with a big impact, ensuring you capture all possible solutions. Think of it as a safety net – it prevents you from falling into the trap of incomplete answers. This seemingly minor detail is a cornerstone of accuracy in algebra, so make it a habit to always include the ± sign.

Incorrectly Isolating the Squared Term

Before applying the square root property, you need to make sure the squared term is completely isolated. This means that everything else needs to be on the other side of the equation. A common mistake is to try and take the square root before isolating the squared term. This will lead to incorrect results because the square root property only works when the squared term is by itself. Always perform the necessary algebraic manipulations, like adding, subtracting, multiplying, or dividing, to isolate the squared term first. This is a critical preparation step, like clearing the stage before a performance. If the squared term isn't properly isolated, you're essentially applying the square root property to the wrong expression, which throws off the entire solution process. So, take your time, double-check your work, and ensure that the squared term is standing alone before you proceed.

Making Arithmetic Errors

Simple arithmetic errors can derail your entire solution. This is especially true when dealing with square roots and negative numbers. A small mistake in addition, subtraction, multiplication, or division can lead to a completely wrong answer. Always take your time and double-check your calculations. It's also a good idea to use a calculator to verify your arithmetic, especially when dealing with more complex numbers or decimals. Think of arithmetic errors as tiny cracks in a foundation – they might seem insignificant at first, but they can weaken the entire structure. In the context of solving equations, a single arithmetic mistake can throw off the entire solution process. So, be vigilant, treat each calculation with care, and double-check your work. A few extra moments spent on accuracy can save you from a lot of frustration down the line.

Squaring Instead of Taking the Square Root

This might seem like a silly mistake, but it happens more often than you think, especially under pressure. Instead of taking the square root of both sides, some students mistakenly square both sides. This completely reverses the process and leads to a much more complicated equation. Remember, the square root property involves taking the square root to "undo" the squaring operation. Squaring both sides would only make things worse. So, always double-check that you're performing the correct operation. This error is like trying to unlock a door by slamming it shut – it's counterproductive and takes you further away from your goal. Make sure you're clear on the fundamental operation required by the square root property, which is, of course, taking the square root. A moment of mindfulness can prevent this misstep and keep you on the right track.

Practice Problems

To really nail this method, practice is key! Here are a few more problems for you to try:

  1. (x - 3)² = 16
  2. (2x + 1)² = 9
  3. (x + 5)² - 4 = 0

Work through these problems, paying close attention to each step. Remember to isolate the squared term, apply the square root property (don't forget the ± sign!), and then isolate x. The more you practice, the more comfortable you'll become with this technique. So, get those pencils moving and conquer these equations!

Conclusion

Solving quadratic equations using the square root property can feel like a breeze once you get the hang of it. Remember, the key is to isolate the squared term, apply the square root property, and then isolate x. Don't forget the ± sign! With practice, you'll be solving these equations like a pro. Keep up the great work, and happy problem-solving!