## College Algebra (11th Edition)

$x=-7$
We rewrite the 4 on the left, so that the base is $2$ on both sides. $4^{x-2}=2^{3x+3}$ $(2^2)^{x-2}=2^{3x+3}$ By the law of exponents: $(a^x)^y=a^{xy}$ $(2^2)^{x-2}=2^{2x-4}$ Then we set the exponents equal, because the two sides with the same base are equal only if the powers are equal too: if $b^m=b^n$ and $b \ne0$ , $b \ne1$ then $m=n$ $2x-4=3x+3$ $-7=x$