Question

а)(y-3)×(y+5)
б)(4m+n)×(2n+m)
в)5x²-(x-1)×(x²-2x)

Answer 1

а)(у-3)х(у+5)=(ху-3х)х(у+5)=ху²+5ху-3ху-15х=ху²+2ху-15х
б)(4m+n)×(2n+m)=8mn+4m²+2n²+mn=9mn+4m²+2n²
в)5x²-(x-1)×(x²-2x)=5x²-(x3-2х²-х²+2х)=5х²-(х3-3х²+2х)=5х²-х3+3х²-2х=8х²-х3-2х=-х3+8х²-2х
х3-это в кубе