6х²+5х-1=5х²+х²+5х-1=(5х²+5х) +(х²-1)=5х(х+1)+(х-1)(х+1)=(х+1)(5х+х-1)=(х+1)(6х-1)=0
(х+1)(6х-1)=0
х1=-1; х2=1/6
2х²-5х-3=2х²+х-6х-3=(2х²-6х)+(х-3)=2х(х-3)+(х-3)=(х-3)(2х+1)=0
(х-3)(2х+1)=0
х1=3; х2=-1/2
2х²-7х+5=2х²-5х-2х+5=(2х²-2х)-(5х-5)=2х(х-1)-5(х-1)=(х-1)(2х-5)=0
(х-1)(2х-5)=0
х1=1; х2=5/2=2,5
4х²-7х-11=4х²-11х+4х-11=(4х²+4х)-(11х+11)=4х(х+1)-11(х+1)=(х+1)(4х-11)=0
(х+1)(4х-11)=0
х1=-1; х2=11/4=2 ,75
3х²-13х-30=