in the biominal expansion of (k + ax)^4 the coefficent of x^2 is 24

Question

given also that the coefficentis 128, find he values of a and k?

Answer 1

(k + ax)^4 = k^4 + 4k^3(ax) + 6k^2(ax)^2 + 4k(ax)^3 + (ax)^4

⇒ 6a^2k^2 = 24 ⇒ ak =2.

The second condition is with error since there is no coefficient given.

Without this, the values of a and k cannot be found with the given information.

Thanks.