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a in (-oo:+oo)
6*(-6*a-8) = -336 // + 336
6*(-6*a-8)+336 = 0
6*(-6*a-8)+336 = 0
288-36*a = 0
288-36*a = 0
288-36*a = 0 // - 288
-36*a = -288 // : -36
a = -288/(-36)
a = 8
a = 8
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