Question

Find the value of the expressions 3x^3-2y^3-6x^2y^2+xy for x=2/3 and y=1/2

Answer 1

Hi!

`3x^3-2y^3-6x^2y^2+xy=\\\\=3\cdot((2)/(3))^3-2\cdot((1)/(2))^3-6\cdot((2)/(3))^2\cdot((1)/(2))^2+(2)/(3)\cdot(1)/(2)=\\\\=3\cdot(8)/(27)-2\cdot(1)/(8)-6\cdot(4)/(9)\cdot(1)/(4)+(1)/(3)=\\\\=(8)/(9)-(1)/(4)-(2)/(3)+(1)/(3)=(8)/(9)-(1)/(4)-(1)/(3)=(32)/(36)-(9)/(36)-(12)/(36)=\boxed{(11)/(36)}`