Answer
$y = C_1 e^{-2t} + C_2 e^{4t}$
Work Step by Step
$y''+2y'-8y = 0$ has characteristic equation $r^2 +2r -8 = 0$
Completing the square:
$(r+1)^2 = 9 \to r=-2,4$
$y = C_1 e^{-2t} + C_2 e^{4t}$
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