Question

for each equation, find k and the value of any missing solutions:
x^2 - kx - 16 = 0 where -2 is one solution of the equation

Answer 1

answer: k = 6, x ∈ {-2, 8}

explanation:

to solve for k: plug -2 in for x and solve.

(-2)^2 - k(-2) - 16 = 0

4 + 2k - 16 = 0

-12 + 2k = 0

2k = 12

k = 6

to find any missing solutions: plug k back in

x^2 - 6x - 16 = 0

factor:

(x - 8)(x + 2) = 0

x ∈ {-2, 8}