Multiply:
(5x−1)(5x+4)

Answer: 25x^2+15x-4
Step-by-step explanation:
Multply 5x by the other 5x
25x^2
Multiply 5x by 4
20x
Multiply -1 by 5x
-5x
Multiply -1 by 4
-4
Add them together
25x^2+20x-5x-4
Combine like terms
20x-5x=15x
25x^2+15x-4