а)7х²-5х-2=0
7х²+2х-7х-2=0
х×(7х+2)-(7х+2)=0
(7х+2)×(х-1)=0
7х+2=0
х-1=0
х=-2
7
х=1
х1=-2 х2=1
б)2007х²+2020х+13=0
2007х²+2007х+13+13=0
2007х×(х+1)+13(х+1)=0
(х+1)×(2007х+13)=0
х+1=0
2007х+13=0
х=-1
х=-13
2007
х1=-1 х2=-13
а)7х²-5х-2=0
7х²+2х-7х-2=0
х×(7х+2)-(7х+2)=0
(7х+2)×(х-1)=0
7х+2=0
х-1=0
х=-2
7
х=1
х1=-2 х2=1
7
б)2007х²+2020х+13=0
2007х²+2007х+13+13=0
2007х×(х+1)+13(х+1)=0
(х+1)×(2007х+13)=0
х+1=0
2007х+13=0
х=-1
х=-13
2007
х1=-1 х2=-13
2007