Answer: {-10, +10}
Step-by-step explanation: A common mistake in this problem would be to say that if x² = 100, x must equal 10.
Remember however that before you do anything else you must set the equation equal to 0.
So our first step is to subtract 100 from both sides to get x² - 100 = 0. Next, factor the left side to get (x + 10)(x - 10) = 0.
So either x + 10 = 0 or x - 10 = 0.
Solving for x in each equation, we have x = -10 or x = +10.
So our answer is not just 10, it's -10 or +10.
I have also attached my work in the image provided.
