Question

Tính:

a) (\(\dfrac{1}{3}\)x+2y).(\(\dfrac{1}{9}\)x²-\(\dfrac{2}{3}\)xy+4y²)                   

b) (x²-\(\dfrac{1}{3}\)).(x⁴+\(\dfrac{1}{3}\)x²+\(\dfrac{1}{9}\))

c) (y-5).(25+5y+y²+2y)

d) (5x+3y).(25x²-15xy+9y²)

Giải chi tiết giúp mình nha.Cảm ơn 

Answer 1

a: \(\left(\dfrac{1}{3}x+2y\right)\left(\dfrac{1}{9}x^2-\dfrac{2}{3}xy+4y^2\right)=\dfrac{1}{27}x^3+8y^3\)

b: \(\left(x^2-\dfrac{1}{3}\right)\left(x^4+\dfrac{1}{3}x^2+\dfrac{1}{9}\right)=x^6-\dfrac{1}{27}\)

c: \(\left(y-5\right)\left(y^2+5y+25\right)=y^3-125\)