For what values of \(j\) does the equation \((2x + 7)(x - 5) = -43 + jx\) have exactly one real solution? Express your answer as a list of numbers, separated by commas.
:D
Let's simplify the equation, getting a quadratic:
(2x + 7)(x - 5) = -43 +jx
2x2 - 3x - 35 = -43 + jx
2x2 - 3x + 8 = jx
2x2 - 3x - jx + 8 = 0
2x2 - (3 + j)x + 8 = 0
This will have only one solution when the discriminant is zero.
a = 2 b = -(3 + j) c = 8
b2 - 4·a·c = 0 ---> [ -(3 + j) ]2 - 4·2·8 = 0 ---> 9 + 6j + j2 - 64 = 0
---> j2 + 6j - 55 = 0
---> (j + 11)(j - 5) = 0
---> j = -11 or j = 5
The possible values of j are either -11 or 5