3(×-2)=×+2. 5-2 (×-1)-4-× (7×+1)-(9×+3)-5​

3(х-2)=х+25-2(х-1)-4-х(7х+1)-(9х+3)-5​

3х-6=х+25-2х+2-4-7х²-х-9х-3-5

3х-6=-7х²-11х+15

7х²+14х-21=0 / :7

х²+2х-3=0

Д= 2*2-4*1*(-3)=4+12=16

√д=4

х1=(-2-4)/2=-3

х2=(-2+4)/2=1