Question

11. Descompuneti in factori :
a) x^2-6x-27 e)x^2+x-2 i)x^2-x-2
b)x^2-4x-5 f)x^2+x-6 j)x^2+4x-12
c)x^2-4x-21 g)x^2+2x-8 k)x^2-2x-3
d)x^2+2x-3 h)x^2-2x-15 L)x^2-x-20

Answer 1

Explicație pas cu pas:

a)x²-6x-27 = x²+3x-9x-27 = x(x+3)-9(x+3) =

= (x+3)(x-9)

b)x²-4x-5 = x²+x-5x-5 = x(x+1)-5(x+1) =

= (x+1)(x-5)

c)x²-4x-21 = x²+3x-7x-21 = x(x+3)-7(x+3) =

= (x+3)(x-7)

d)x²+2x-3 = x²-x+3x-3 = x(x-1)+3(x-1) =

= (x-1)(x+3)

e)x²+x-2 = x²-x+2x-2 = x(x-1)+2(x-1) =

= (x-1)(x+2)

f)x²+x-6 = x²-2x+3x-6 = x(x-2)+3(x-2) =

= (x-2)(x+3)

g)x²+2x-8 = x²-2x+4x-8 = x(x-2)+4(x-2) =

= (x-2)(x+4)

h)x²-2x-15 = x²+3x-5x-15 = x(x+3)-5(x+3) =

= (x+3)(x-5)

j)x²+4x-12 = x²-2x+6x-12 = x(x-2)+6(x-2) =

= (x-2)(x+6)

k)x²-2x-3 = x²+x-3x-3 = x(x+1)-3(x+1) =

= (x+1)(x-3)

L)x²-x-20 = x²-5x+4x-20 = x(x-5)+4(x-5) =

= (x-5)(x+4)