Giải các phương trình:
a) \(\dfrac{1}{x-2}\) + 3 = \(\dfrac{3-x}{x-2}\)
b) \(\dfrac{8-x}{x-7}\) - 8 = \(\dfrac{1}{x-7}\)
c) \(\dfrac{1}{x-1}\) + \(\dfrac{2x}{x^2+x+1}\) = \(\dfrac{3x^2}{x^3-1}\)
d) \(\dfrac{y+5}{y^2-5y}\) - \(\dfrac{y-5}{2y^2+10y}\) = \(\dfrac{y+25}{2y^2-50}\)