4(x² - 2) = 28
1. Distribute the 4
4x² - 8 = -28
2. Plug in 3 and -3
4(3)² - 8 = 28
4(-3)² - 8 = 28
3. Square 3 and -3
4(9) - 8 = 28
4(9) - 8 = 28
28 = 28
The reason both answers are the same is because whenever you put a negative number to an even power, the result becomes positive because any negative multiplied by a negative number is always positive.
28 = 28
