Question

How do you solve this?

Answer 1

You X to the second power.. 4 to the second power is 16 and 16-16=0 so x=4

Answer 2

Add 16
x² - 16 = 0
    + 16 +16

x² = 16
Take square root

$\sqrt{x^2} = \sqrt{16}$

Remember when you take the square root of a perfect square you get two values. +ve and -ve

x = -4
x =  4

because (-4)² = 16
               ( 4)² = 16