Question

(x+3)(3x-7)=0
Помогите люди добрие.

Answer 1

(х+3)(3х-7)=0

3х²-7х+9х-21=0

3х²+2х-21=0

D=b²-4ac

D=4-4*3(-21)

D=256

x1=-b+√D/2a

x1=-2+16/6

x1=2.(3)

x2=-b-√D/2a

x2=-2-16/6

x2=3