Question

Выполните умножение
(5a-7)(3a+1)
(3b+7)(4-3b)
5(x+2)(x+3)
-6(a+4)(a-1)

Answer 1

$15a { }^{2} + 5a - 21a - 7 \\15a {}^{2} - 16a - 7$
$12b - 9b {}^{2} + 28 - 21b \\ - 9b {}^{2} - 9b + 28$
$5x {}^{2} + 15x + 10x + 30 \\ 5x {}^{2} + 25 + 30$