Simplify the expression

(-y+4)(2y-1)

Expanding the expression using FOIL method, we get:

(-y+4)(2y-1) = -2y^2 + y + 8y - 4
Combining like terms, we get:
-2y^2 + 9y - 4
Therefore, (-y+4)(2y-1) simplifies to -2y^2 + 9y - 4.