x^2-3x+4x-12+x^2+4x-5x-20
2x^2-32=0
x^2=16
x= -4;4
(x+4)*(x-3)+(x-5)*(x+4)=0
x^2-3x+4x-12+x^2+4x-5x-20=0
x^2=32
x^2=32:2
x1=4
x2=-4
x^2-3x+4x-12+x^2+4x-5x-20
2x^2-32=0
x^2=16
x= -4;4
(x+4)*(x-3)+(x-5)*(x+4)=0
x^2-3x+4x-12+x^2+4x-5x-20=0
2x^2-32=0
x^2=32
x^2=32:2
x^2=16
x1=4
x2=-4