7/(3х-1) - 5/(2х-1):(3х-1)/(4х^2-1) =
1) 5/(2x-1): (3x-1)/(4x^2-1) = 5/(2x-1)*((2x-1)(2x+1))/(3x-1)= 5*(2x-1)(2x+1)/ ((2x-1)(3x-1)) = 5*(2x+1)/(3x-1)
2) 7/(3x-1) - 5(2x+1)/(3x-1) = (7-5(2x+1)) / (3x-1) = (7-10x-5)/(3x-1) = (2-10x) / (3x-1) = 2(1-5x)/(3x-1)