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Question:

Solve for x:

4x² – 61 = 135

A
x = -7 or 7

Explaination

Step 1: Add 61 on both sides

The first step in solving this problem is to add 61 from both sides of the equation.

4x² – 61 + 61 = 135 + 61

You should then carry out the addition of the numbers on both sides of the equation.

4x² = 196

Step 2: Divide by 4 on both sides

We then divide both sides of the equation by 4.

(4 x²)/4 = 196/4

x² = 49

Step 3: Take the square root on both sides

The final step is to take the square root on both sides to solve for x.

x² = 49

√x² = √49

x = 7 0r -7

If you are asking WHY the -7 gets included as well, it’s because any negative number squared, is positive.

7 x 7 = 49

But so does:

-7 x -7 = 49

Since both options work, we have to include both.

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