Question

$225*20^2+15^2-300^x-225=0$

Answer 1

$225\cdot 20^2+15^2-300^x}-225=0\\\\15^2\cdot 20^2+\underline {15^2}-300^{x}-\underline {15^2}=0\\\\(15\cdot 20)^2-300^{x}=0\\\\300^{x}=300^2\\\\x=2$