(х-1)(х-7)(х-4)(х+2)=40

Question

(х-1)(х-7)(х-4)(х+2)=40

Answer 1

(х-1)(х-4)(х-7)(х+2)=40
(х2-4х-х+4)(х2+2х-7х-14)=40
(х2-5х+4)(х2-5х-14)=40
х2-5х=y
(y+4)(y-14)=40
y2-10y-96=0
D= b2-4ac
D=484
t=-6
t=16
х2--5х=-6; х2-5х=16
х=2; х=3