QUESTION $6$

Find the exact solution for $x,$ if there is no solution write no solution:

$6\mathrm{.}1-5e^{-4x-1}+4=64$

$6\mathrm{.}2,e^{2x}-e^x-72=0$

$6\mathrm{.}3,ln(-3x)=ln(x^2-6x)$

$6\mathrm{.}4log(x+12)=log(x)+log(12)$

$6\mathrm{.}5co{s}^2(x)=cos(x)$ on $[0,2).$

$6\mathrm{.}62ta{n}^2(x)=3sec(x)$ on $[0,2).$