Question

Thực hiện phép tính:
a)(5x²-2x+1).(2x²-3x)
b)(18x⁴y³-6x²y³+12x³y⁴z):6x²y³
c)(6x³-7x²-x+1):(2x+1)

Answer 1

a) \(\left(5x^2-2x+1\right)\left(2x^2-3x\right)\)

\(=10x^4-15x^3-4x^3+6x^2+2x^2-3x\)

\(=10x^4-19x^3+8x^2-3x\)

Answer 2

b) \(\left(18x^4y^3-6x^2y^3+12x^3y^4z\right)\)

\(=6x^2y^3\left(3x^2-1+2xyz\right)\)

\(\Rightarrow\left(18x^4y^3-6x^2y^3+12x^3y^4z\right):6x^2y^3\)

\(=\left[6x^2y^3\left(3x^2-1+2xyz\right)\right]:6x^2y^3\)

\(=3x^2+2xyz-1\)

Answer 3

c) \(\left(6x^3-7x^2-x+1\right)\)

\(=3x^2\left(2x+1\right)-5x\left(2x+1\right)+2\left(2x+1\right)-1\)

\(=\left(2x+1\right)\left(3x^2-5x+2\right)-1\)

\(\Rightarrow\left(6x^3-7x^2-x+1\right):\left(2x+1\right)\)

\(=\left[\left(2x+1\right)\left(3x^2-5x+1\right)-1\right]:\left(2x+1\right)\)

\(=3x^2-5x+1\) (Dư \(-1\))