Question

Bài 1 Thực hiện phép tính

a) (x-1)(x-2)(x-3)

b) (x^2 +x+1)(x^2-1)(x^2-x+1)

c) (2x-5)(4-3x)-(3x+11)(5-2x)-15(2x-5)

d)(x^2-2x+3)(3x-5)-(x^2+x-1)(2x+7)

mk dag can gấp nhá nhanh lên cảm ơn

Answer 1

a: \(\left(x-1\right)\left(x-2\right)\left(x-3\right)\)

\(=\left(x^2-3x+2\right)\left(x-3\right)\)

\(=x^3-3x^2-3x^2+9x+2x-6\)

\(=x^3-6x^2+11x-6\)

b: \(\left(x^2+x+1\right)\left(x^2-1\right)\left(x^2-x+1\right)\)

\(=\left(x-1\right)\left(x^2+x+1\right)\cdot\left(x+1\right)\left(x^2-x+1\right)\)

\(=\left(x^3-1\right)\left(x^3+1\right)\)

\(=x^6-1\)

c: \(=8x-6x^2-20+15x-\left(15x-6x^2+55-10x\right)-30x+75\)

\(=-6x^2-7x+55+6x^2-5x-55\)

\(=-12x\)

d: \(\left(x^2-2x+3\right)\left(3x-5\right)-\left(x^2+x-1\right)\left(2x+7\right)\)

\(=3x^3-5x^2-6x^2+10x+9x-10-\left(x^2+x-1\right)\left(2x+7\right)\)

\(=3x^3-11x^2+19x-10-\left(2x^3+7x^2+2x^2+7x-2x-7\right)\)

\(=3x^3-11x^2+19x-10-2x^3-9x^2-5x+7\)

\(=x^3-20x^2+14x-3\)