Question

5ⁿ * 5¹ - 11 * 5ⁿ <80

Answer 1

$5^ncdot5 - 11cdot5^n<80, \ 5^ncdot(5 - 11)<80, \ -6cdot5^n<80, \ 5^n>-13 frac{1}{3} , \ 5^n>0>-13 frac{1}{3} , \ nin R.$