$$log 2x + log x^{2}= log 16$$
log2x + logx2 = log 16 using a property of logs on the left hand side
log(2x*x2) = log (16 ) so....equating the expressions in the parentheses, we have
2x3 = 16 divide both sides by 2
x3 = 8 take the cube root of both sides
x = 2