Solve for x:
4x² – 61 = 135

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.