2y²(6y-1)+3y(y-4y²)

To simplify the expression 2y²(6y-1)+3y(y-4y²), we will first distribute the terms.

(2y²)(6y) - (2y²)(1) + (3y)(y) - (3y)(4y²)

Then, simplify each term:

12y³ - 2y² + 3y² - 12y³

Now combine like terms:

(12y³ - 12y³) + (3y² - 2y²)

12y³ - 12y³ is eliminated since they cancel each other out.

This leaves:

3y² - 2y²

Finally, the simplified expression is:

y².