Question

[3(x-2)-2(x-1)]•[x(x+3)-x(x+2)+5]

Answer 1

[3(x-2)-2(x-1)]*[x(x+3)-x(x+2)+5]=
(3x-6-2x+2)(x²+3x-x²-2x+5)=
(x-4)(x+5)=
x²+5x-4x-20=
x²+x-20
egalam cu zero x²+x-20=0 si aflam discriminantul,
sau mai usor egalam cu zero (x-4)(x+5):
(x-4)(x+5)=0
x-4=0=>x=4
x+5=0=>x=-5