Answer:
a = 8
Step-by-step explanation:
x-1 = 0
x = 1
let x³ + ax² -x -8 be p(x)
hence, p(1) = (1)³ + a(1)² -1 -8 = 0 (since, x-1 is a factor)
= 1 + a - 1-8
= a - 8 = 0
therefore, a = 8
