What is the answer to x2 = 121.

Step-by-step explanation: A common mistake in this problem would be to say that if x² = 121, x must equal 11.

However, you must set the equation equal to 0 first.

So our first step is to subtract 121 from both sides to get x² - 121 = 0.

Next, factor the left side to get (x + 11)(x - 11) = 0

So either x + 11 = 0 or x - 11 = 0.

Solving each equation from here, we find that x = -11 or x = 11.

So our answer is not just 11, it's {11, -11}.