Question

упростите выражение
(2а-1)(а+2)
ху-9х-(х-2ху)
(2х-3у^2)(2х+3у^2)

Answer 1

1)
$(2a - 1)(a + 2) = \\ = 2 {a}^{2} + 4a - a - 2 = \\ = 2 {a}^{2} + 3a - 2$
2)
$xy - 9x - x + 2xy = \\ = 3xy - 10x$
3)
$(2x - 3 {y}^{2} )(2x + 3 {y}^{2} ) = \\ = 4 {x}^{2} + 6x {y}^{2} - 6x {y}^{2} - 9 {y}^{4} = \\ = 4 {x}^{2} - 9 {y}^{4}$