Легко!
a) (-2x^2+7x-3)/(2x^2-x) = (-2x^2+x+6x-3)/(x(2x-1)) =
= (2x-1)(-x+3)/(x(2x-1)) = (3-x)/x
б) (-3x^2+x+2)/(9x^2-4) = (-3x^2+3x-2x+2)/(9x^2-4) =
= (3x+2)(-x+1)/((3x-2)(3x+2)) = (1-x)/(3x-2)
в) (5x^2+4x-1)/(5x^2-6x+1) = (x+1)(5x-1)/((x-1)(5x-1)) =
= (x+1)/(x-1)
г) (x^3+4x^2-9x-36)/(x^2+x+12) = (x+4)(x^2-9)/((x-3)(x+4)) =
= (x^2-9)/(x-3) = (x-3)(x+3)/(x-3) = x+3
д) (-x+√x+2)/(√x-2) = -(x-√x-2)/(√x-2) = -(√x+1)(√x-2)/(√x-2) = -√x - 1