Question

calcule (x+y)² - (x-y)²


calcule (x+3)²​

Answer 1

Resposta:

1. calcule (x+y)² - (x-y)²

(x+y)² - (x-y)² = 4xy

 

2. calcule (x+3)²​

(x+3)² = x²+6x+9

Explicação passo a passo:

1. calcule (x+y)² - (x-y)²

(x+y)² - (x-y)² = (x+y).(x+y)-(x-y).(x-y) = x.x+xy+yx+y.y-x.x-x.(-y)-yx-y.(-y)

(x+y)² - (x-y)² = x²+2xy+y²-x²+2xy-y² = x²-x²+2xy+2xy+y²-y² = 0+4xy+0 = 4xy

(x+y)² - (x-y)² = 4xy

 

2. calcule (x+3)²​

(x+3)²​ = (x+3).(x+3) = x.x+x.3+3x+3.3 = x²+3x+3x+9 = x²+6x+9

(x+3)² = x²+6x+9