Question

А)-5a³(2a²-a-3) d)(3c-a)(2c-5a) b)(3x+2y)² c)7+x(x-1)=x²-1 v)3(2x-4)=2x-(5x+9)

Answer 1

А). -5а³(2а²-а-3)= -5а³·2а²-5а³·(-а)·(-3)= -10а^5+5а⁴+15а³

б). (3с-а)(2с-5а)=6с-15ас-2ас+5а²=5а²-17ас+6с

в). (3х+2у)²= (2х)²+2·2х·3у+(3у)²= 4х²+12ху+9у²

г). 7+х(х-1)=х²-1
7+х²-х=х²-1
7-х=-1
-х=-1-7
-х=-8
х=8

д). 3(2х-4)=2х-(5х+9)
6х-12=2х-5х-9
6х-12= -3х-9
6х+3х= -9+12
9х=3
х=⅓