Answer: C = -4
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Work Shown:
C(x+2) - (x+2)(x-2) = 0
(x+2)(C-(x-2)) = 0
(x+2)(C-x+2) = 0
x+2 = 0 or C-x+2 = 0
x = -2 or x = C+2
If we want one solution only, then we must make C+2 = -2 which solves to C = -4
If C = -4, then x = C+2 = -4+2 = -2 which matches with the first solution mentioned. If C is anything else but -4, then we'd have two different solutions (eg: C = 10 leads to x = C+2 = 12 as the other solution)
