Question

Sa se descompuna in factori:
a) 16x^2-36
b) x^2+9x+20
c) 9(x-2)^2-4x^2
d) x^2+6x-4^2-4+8

^ este ridicarea la putere

Answer 1

a)16x²-36=(4x)²-6²=(4x-6)(4x+6)
b)x²+9x+20=x²+4x+5x+20=x(x+4)+5(x+4)=(x+4)(x+5)
c)9(x-2)²-4x²=(3(x-2))²-(2x)²=(3(x-2)-2x)(3(x-2)+2x)=(3x-6-2x)(3x-6+2x)=
=(x-6)(5x-6)

Answer 2

a)
$16x^{2} - 36 = 4(4 x^{2} -9)= 4(2x-3)(2x+3)$
b)
$x^{2} + 9x + 20 = x^{2} + 5x + 4x + 20= \\ =x(x+5)+4(x+5) = (x+4)(x+5)$
c)
[tex]9( x-2)^2 - 4 x^{2} = \\ = (3(x-2)-2x)(3(x-2)+ 2x) = \\ = (3x-6-2x)(3x-6+2x)= \\ =(x-6)(5x-6)[/tex]
d)
$x^{2} +6x - 4^2 - 4 +8= x^{2} +6x - 16-4 + 8 = \\ = x^{2} + 6x - 12$