Question

Thực hiện phép tính :

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

b) \(\left(x^2-2xy+y^2\right)\left(x-y\right)\)

Answer 1

a) (x² – 2x + 3) (x – 5)

= x³ - 5x² - x² +10x + x – 15

= x³ – 6x² + x -15

b) (x² – 2xy + y²)(x – y)

= x³ - x² y - 2x² y + 2xy² +xy²- y³

= x³ - 3x² y + 3xy² - y³

Answer 2

a) (x² – 2x + 3) ( 1/2x – 5) = \(\dfrac{1}{2}\)x³ – 5x² – x² + 10x +\(\dfrac{3}{2}\)x - 15

= \(\dfrac{1}{2}\)x³ – 6x² + \(\dfrac{23}{2}\) x – 15.

b) (x² – 2xy + y²)( x – y) = x³ – x²y – 2x²y + xy² – y³ = x³ – 3x²y + 3xy² – y³

Answer 3

(x2 – 2x + 3) (1/2x – 5) =1/2x3 – 5x2 – x2 +10x + 3/2x – 15 = 1/2x3 – 6x2 + 23/2 x -15 b) (x2 – 2xy + y2)(x – y) = x3 – x2 y – 2x2 y + 2xy2 +xy2– y3 = x3 – 3x2 y + 3xy2 – y3