A Tricky Exponential Equation | Only Geniuses Can Solve This

[@leonardobuitrago-b9w]

I solved the last one in this way, but I dont know if it is a correct way 4^x - 2^x = 240 2^2x - 2^x = 2^4 * 5 *3 2^x(2^x - 1) = 2^4 (2^2 +1)(2^2 -1) 2^x(2^x - 1) = 2^4 (2^4 -1) x = 4

[@titoucarotte5238]

You forgot to solve for x in the last one, you stopped at y1 and y2 oh and y1 = 16 not 17 Here's what I got : y=2^x So 2^x=16 or 2^x=-15 log2^x=log2^4 or undefined xlog2=4log2 x=4