Substitute 6x² from 3y-2x+5x²

This does not make sense to me.

if you mean "subtract" then that would be

3y-2x-x^2

3y-x2

To substitute 6x² into the expression 3y-2x+5x², we need to replace every instance of x² with 6x².

First, let's rewrite the expression, indicating where we will make our substitution:
3y - 2x + 5x²

Now, let's substitute 6x² into the expression:
3y - 2x + 5(6x²)

To simplify the expression further, we need to distribute the 5 to the terms inside the parentheses:
3y - 2x + 30x²

Therefore, by substituting 6x² into 3y-2x+5x², the expression simplifies to 3y - 2x + 30x².