Question

If (x-5) is a factor of x cube - 3x cube + x + 5a then find the value of a

Answer 1

x³-3x³+x+5a=0

(x-5=0)

(x=+5)

Substituting in the polynomial we get:

(5)³-3(5)³+5+5a=0

125-3(125)+5+5a=0

125-375+5+5a=0

-245+5a=0

a=245÷5

a=5