(a) Let u=7^x. Using the rules for powers show that i) 7^x-1 = u/7 and ii) 7^2x-1 = u^2/7

Question

(b) By making the substitution u=7^x and using part (a), derive a hidden quadratic equation

7^2x-1 +4×7^x-1 - 1/14 = 0

and hence find all solutions to the above equation.

Answer 1

so, did you try the hint?
Time to start showing some of your work ...