Answer:
Explanation:
(3x - 1)(x + 5) = k
3x^2 - x - 15x - 5 - k = 0
3x^2 - 16x - 5 - k = 0
a = 3
b = - 16
c = - 5 - k
The discriminate must be 0
sqrt(b^2 - 4a*c) = 0 Substitute
sqrt( (-16)^2 - 4(3)(-5-k) ) = 0 Square both sides.
(-16)^2 - 12(-5 - k) = 0
256 + 60 + 12k = 0
316 + 12k = 0
12k = - 316
k = - 316/12
k = -26.3