Question

Раскройте скобки:
2x(x+7)-2(x-7)(x+2)-(x+2)(x+7)

Answer 1

2х²+14х-2(х²+2х-7х-14)-(х²+7х+2х+14)=2х²+14х-2х²-4х+14х+28-х²-7х-2х-14=2х²-2х²-х²+14х-4х+14х-7х-2х+28-14=

= -х²+15х+14