Question

2X^2+3X=27 X=?5x^3-3x^2-32x-12 因式分解

Answer 1

2X^2+3X=27

2X^2+3X-27=0

(X-3)(2X+9)=0

X=3,X=-9/2

5x^3-3x^2-32x-12

=(5x^3-15x^2)+(12x^2-36x)+(4x-12)

=5x^2(x-3)+12x(x-3)+4(x-3)

=(x-3)(5x^2+12x+4)

=(x-3)(5x+2)(x+2)