Multiply

-5x+4 by 4x^2+x

(-5X^2+4)(4X^2+X).

When multiplying, you add the exponents.

1. Multiply -5x^2 by each term in the 2nd parenthesis.

2. Multiply 4 by each term in the 2nd parenthesis.

3. Combine like-terms.

-20X^3-5X^2 + 16X^2+4X =
-20X^3+11X^2+4X.