Question

phân tích đa thức thành nhân tử:

d) x³-4x²-9x+36

e) (x+1)³+(2x-1)³

g) x³+3x²-4x-12

h) x³-4x²+4x-1

Answer 1

d) x³-4x²-9x+36

=x²(x-4)-9(x-4)

=(x-4)(x²-9)

=(x-4)(x+3)(x-3)

e)(x+1)³+(2x-1)³

=x³+3x²+3x+1+8x³-12x²+6x-1

=9x³-9x²+9x

=9x(x²-x+1)

g)x³+3x²-4x-12

=x²(x+3)-4(x+3)

=(x+3)(x²-4)

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

h) x³-4x²+4x-1

=x³-1-4x²+4x

=(x-1)(x²+x+1)-4x(x-1)

=(x-1)(x²+x+1-4x)

=(x-1)(x²-3x+1)