Answer:
given p(x)= 5x^3-7x^2-ax-28
(x-4) is a factor of 5x^3-7x^2-ax-28
=>p(4)=0
=>5(4)^3-7(4)^2-4a-28=0
=>320-112-4a-28=0
=>-4a=-180
=>a=180/4
=>a=45
Step-by-step explanation:
x=a
