posted by Nicky .
Write the expression as a single logarithm. Ln(e^3y)+ln(ey)-4
e^(ln x) = x
ln(e^x) = x
ln and e^ are inverse functions, just like x^2 and √x
Assuming no typos, I see
ln(e^3y)+ln(ey)-ln(e^4) = ln(e^3y * ey / e^4) = ln(y^2) = 2ln(y)