$\displaystyle 7^{2x}=3*2^{x+2}$
I know you have to use logs but i cant get the x's on one side after i do that.
$\displaystyle (7^2)^x=3\cdot 2^x\cdot 2^2$
$\displaystyle 49^x=12\cdot 2^x$
$\displaystyle \left(\frac{49}{2}\right)^x=12$
Apply log in both members
$\displaystyle \log\left(\frac{49}{2}\right)^x=\log 12$
$\displaystyle x=\frac{\log 12}{\log\frac{49}{2}}=\frac{2\log 2+\log 3}{2\log 7-\log 2}$