Question

4) Descompuneti in factori:
a) x³+2x²-16(x+2)=
b) 36(x-2)²-25(x+1)²=
c)16(x+5)²-9(2x-3)²=
VA ROG!

Answer 1

a) x³+2x²-16(x+2)=x²(x+2)-16(x+2)=(x+2)(x²-16)=(x+2)(x+4)(x-4)
b) 36(x-2)²-25(x+1)²=[6(x-2)-5(x+1)][6(x-2)+5(x+1)]=
=(6x-12-5x-5)(6x-12+5x+5)=(x-17)(11x-7)
c)16(x+5)²-9(2x-3)²=[4(x+5)-3(2x-3)][4(x+5)+3(2x-3)]=
=(4x+20-6x+9)(4x+20+6x-9)=(29-2x)(10x+11)

Answer 2

a. x^2 (x+2) -16(x+2) = (x+2)(x^2 - 16) = (x+2)(x-4)(x+4)
b. (6(x-2) -5(x+1))(6(x-2) + 5(x+1)) =
     (6x-12-5x-5)(6x-12+5x+5) =
     (x-17)(11x-7)
c.(4(x+5) - 3(2x-3))(4(x+5) + 3(2x-3)) = calcule simple ca la b. Le faci singur.