Question

Efetue e simplifique:

x² - (x + 10)²

Answer 1

x²-(x+10)²=x²-(x²+20x+100)=x²-x²-20x-100=-20x-100

-20x-100=0 ⇒ -20x=100 ⇒ x=-100/20 ⇒ x=-5

Answer 2

x2-(x+10)2
2x-2x=20
=20