Question

Descompuneți,folosind metode combinate :
x²+8x+15=
x²+2x-8=
(5x-3)²-(3x-4)²=
x²(a+1)-9a-9=
25x²-a²+2a-1=
Va rog urgent!!

Answer 1

x²+8x+15=x²+3x+5x+15=x(x+3)+5(x+3)=(x+3)(x+5)
x²+2x-8=x²-2x+4x-8=x(x-2)+4(x-2)=(x-2)(x+4)
(5x-3)²-(3x-4)²= (5x-3+3x-4)(5x-3-3x+4)= (8x-7) (2x+1)
x²(a+1)-9a-9=x²(a+1)-9(a+1)=(a+1)(x²-9)=(a+1)(x+3)(x-3)
25x²-a²+2a-1=(5x)²-(a²-2a+1)=(5x)²-(a-1)²=(5x+a-1)(5x-a+1)