= (3х +у)* 2(х-2у) / (х - 2у)*(3х+у)^2 = 2(3х+у) / (3х+у)^2 = 2/(3x + y)
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= (2x - 1)^2 * (x + 1) / 5(x+1)*(2x-1) = (2x - 1) / 5
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= (x - y)*(x - y) * 18x^2 / 27x^3 * y(x - y) = 6(x+y) / 9xy = 2(x+y) /3xy