Question

Descompunerii in factori : x^2-4x-21;x^2+x-6; x^2+4x-12;x^2-6x-27;x^2+5x+6;x^2+9x+14;x^2+7x+6;x^-5x+6;x^2-10x+16;x^2-13x+40;x^2-12x+27

Answer 1

x^2-4x-21=x^2-7x+3x-21=x(x-7)+3(x-7)=(x-7)(x+3)

x^2+x-6=x^2+3x-2x-6=x(x+3)-2(x+3)=(x+3)(x-2)

 x^2+4x-12= x^2+6x-2x-12=x(x+6)-2(x+6)=(x+6)(x-2)

x^2-6x-27=x^2-9x+3x-27=x(x-9)+3(x-9)=(x-9)(x+3)

x^2+5x+6=x^2+3x+2x+6=x(x+3)+2(x+3)=(x+3)(x+2)

x^2+9x+14=x^2+2x+7x+14=x(x+2)+7(x+2)=(x+2)(x+7)

x^2+7x+6=x^2+6x+x+6=x(x+6)+(x+6)=(x+6)(x+1)

x^2-5x+6=x^2-3x-2x+6=x(x-3)-2(x-3)=(x-3)(x-2)

x^2-10x+16=x^2-2x-8x+16=x(x-2)-8(x-2)=(x-2)(x-8)

x^2-13x+40=x^2-5x-8x+40=x(x-5)-8(x-5)=)x-5)(x-8)

x^2-12x+27 =x^2-9x-3x+27 =x(x-9)-3(x-9)=(x-9)(x-3)