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x in (-oo:+oo)
15.48/12.9 = x/42.8 // - x/42.8
15.48/12.9-(x/42.8) = 0
15.48/12.9-0.02336449*x = 0
1.2-0.02336449*x = 0 // - 1.2
-0.02336449*x = -1.2 // : -0.02336449
x = -1.2/(-0.02336449)
x = 51.35999117
x = 51.35999117
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