Question

几道初二分解因式题···x²+14x+40 2x²-7x-15 3x+x-24 10y²-

Answer 1

x²+14x+40=x^2+(10+4)x+10*4=(x+4)(x+10)

2x²-7x-15=2x^2-(10-3)x-3*5=(2x+3)(x-5)

3x^2+x-24=3x^2+(9-8)x-3*8=(3x-8)(x+3)

10y²-13y-3=2*5x^2-(15-2)x-3=(5x+1)(2x-3)