Simplify the following expression: 12y2÷4y- 3x5y

To simplify the expression \frac{12y^2}{4y} - 3x^5y , we need to divide 12y^2 by 4y and then subtract 3x^5y from that result.

Step 1: Simplify \frac{12y^2}{4y}
\frac{12y^2}{4y} = 3y

Step 2: Subtract 3x^5y from 3y
3y - 3x^5y = y(3 - 3x^5)

Therefore, the simplified expression is y(3 - 3x^5) .

\textbf{Answer:} y(3 - 3x^5)