Carcass wrote:
If a3−a2−a+1=0, what is the product of all possible values of a?
A. -1
B. 0
C. 1
D. 2
E. 4
We can factor the left side in parts.
Given:
a³ − a² − a + 1 = 0Factor in parts:
a²(a − 1) - 1(a - 1) = 0Combine to get:
(a² - 1)(a − 1) = 0Since the first expression (and brackets) is a difference of squares, we can factor it as follows:
(a + 1)(a - 1)(a - 1) = 0There are two unique solutions:
a = 1 and
a = -1, which means the product of all possible values of a = (
1)(
-1) =
-1Answer: A