2y²(6y-1)+3y(y-4y²)

To simplify the expression, you can start by distributing both terms in the expression.

First, distribute the first term, 2y², to both terms in the parentheses:

2y²(6y-1) = 12y³ - 2y²

Next, distribute the second term, 3y, to both terms in the parentheses:

3y(y-4y²) = 3y² - 12y³

Finally, combine the like terms:

12y³ - 2y² + 3y² - 12y³ = (12y³ - 12y³) - 2y² + 3y² = - 2y² + 3y² = y²

So, the simplified expression is y².