Question

Answer 1

a: \(\dfrac{2}{5}xy\left(x^2y-5x+10y\right)\)

\(=\dfrac{2}{5}xy\cdot x^2y-\dfrac{2}{5}xy\cdot5x+\dfrac{2}{5}xy\cdot10y\)

\(=\dfrac{2}{5}x^3y^2-2x^2y+4xy^2\)

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

\(=x^2\cdot x^2+x^2\cdot2x-x^2\cdot1-2x\cdot1\)

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

c: (3x-2)(3x+2)(3-x)

\(=\left(9x^2-4\right)\left(3-x\right)\)

\(=27x^2-9x^3-12+4x\)

Answer 2

a)

  

Answer 3

b)(x² - 1)(x² + 2x)

= x².x² + x².2x - 1.x² - 1.2x

= x⁴ + 2x³ - x² - 2x

Answer 4

c) (3x - 2)(x + 2)(3 - x)
= (9x² - 4)(3 - x)

= 9x².3 - 9x².x - 4.3 + 4.x

= 27x² - 9x³ - 12 + 4x

= -9x³ + 27x² + 4x - 12