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4/5-((1/4)*x) = 39/40 // - 39/40
4/5-((1/4)*x)-(39/40) = 0
(-1/4)*x+4/5-39/40 = 0
-1/4*x-7/40 = 0 // + 7/40
-1/4*x = 7/40 // : -1/4
x = 7/40/(-1/4)
x = -7/10
x = -7/10
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