If possible, use the Binomial Theorem to find the coefficient of x $^3$ y$^7$ in

the binomial expansion of $(4$x $+5$y$)^10.$ If it is not possible, explain why.

If possible, use the Binomial Theorem to find the coefficient of x $^5$ in

the binomial expansion of $($x $2$x $2)^27.$ If it is not possible, explain why.