In the expansion the coefficients of and are 10 and 25 respectively, where a and b are constants.

Find the values of a and b.

I have tried to rewrite the equation in the form and prepare it for binomial expansion but I am getting something like

Which we can use to solve for a and b but it is extremely long and tedious and I am sure there must be an easier way to get around it. Any help at all is appreciated.