Question

A/ \(\left(x-2\right)^2-\left(x-3\right)\left(x+1\right)\) 

B/\(x^3-2x^2-5x-10:x-2\)

Thực hiện phép tính

Answer 1

a: =x^2-4x+4-x^2+2x+3

=-2x+7

b: \(=\dfrac{x^2\left(x-2\right)-5x+10-20}{x-2}=x^2-5+\dfrac{-20}{x-2}\)

Answer 2

A)

\(\left(x-2\right)^2-\left(x-3\right)\left(x+1\right)\\ =x^2-4x+4-\left(x^2+x-3x-3\right)\\ =x^2-4x+4-x^2-x+3x+3\)

\(=x^2-x^2-4x+3x-x+4+3\)

\(=-2x+7\)

B)

\(\left(x^3-2x^2-5x-10\right):\left(x-2\right)\\ =\left[x^2\left(x-2\right)-5\left(x+2\right)\right]:\left(x-2\right)\\ =\left[x^2\left(x-2\right)+5\left(x-2\right)\right]:\left(x-2\right)\\ =\left(x-2\right)\left(x^2+5\right):\left(x-2\right)\\ =x^2+5\)