Question

calcule o produto da soma pela diferença
a) (X+3)(x-3)
B)(4-7x)(4+7x)
c) (5m+2n)(5m-2n)

Answer 1

a)
(x+3)(x-3) = x²-9
b)
(4-7x)(4+7x) = 4² - (7x)² = 16 - 49x²
c)
(5m+2n)(5m-2n) = (5m)² - (2n)² = 25m² - 4n²

Answer 2

$a) (x+3)(x-3) \\x^2- 3x +3x-9\\x^2-9\\\\ b)(4-7x)(4+7x)\\16+28x - 28 x - 49x^2 \\ 16-49x^2\\\\ c) (5m+2n)(5m-2n)\\25m^2-10mn+10mn-4n^2\\25m^2-4n^2$