Question

If -1 is zero of polynomial p(x) =ax square -3(a-1)x-1 then find the value of a.

Answer 1

a = 1

Explanation:

Since x = - 1 is a zero of p(x) then p(- 1) = 0

Substitute x = - 1 into p(x)

p(- 1) = a(- 1)² - 3(a - 1)(- 1) - 1 = 0, that is

a + 3(a - 1) - 1 = 0

a + 3a - 3 - 1 = 0

4a - 4 = 0 ( add 4 to both sides )

4a = 4 ( divide both sides by 4 )

a = 1