Question

(0.9x+0.7y)(0.81x^2-0.63xy+0.49y^2)​

Answer 1

Please tell whether it is correct or not

Answer 2

According to $a^3+b^3=(a+b)(a^2-ab+b^2)$,

$(0.9x+0.7y)(0.81x^2-0.63xy+0.49y^2) \\ \\ (0.9x+0.7y)((0.9x)^2-(0.9x \times 0.7y)+(0.7y)^2) \\ \\ (0.9x)^3+(0.7y)^3 \\ \\ 0.729x^3+0.343y^3$

Hope this helps. ^_^