Question

Simplifiquem as expressões (x-3) ^2- (x-2) ×(x+2)-(x+1)^2

Answer 1

(x-3)² - (x-2) . (x+2) - (x+1)² =
x²-6x+9 - (x²-2²)- (x²+2x+1) =
x²-6x+9 - x²-4 -x²-2x-1 =
x²-x²-x²-6x-2x+9-4-1 = 
-x²-8x+4

Answer 2

(x-3) . (x-3) = x² - 3x - 3x + 9 = x² - 6x + 9
(x-2) . (x+2) = x² + 2x - 2x - 4 = x² - 4
(x+1) . (x+1) = x² + x + x + 1 = x² + 2x + 1

(x² - 6x + 9) - (x² - 4) - (x² + 2x + 1)
x² - x² - x² = -x²
-6x - 2x = -8x
9 + 4 - 1 = 12

-x² - 8x + 12 = 0
ou 
x² + 8x - 12 = 0