а) а²+3/а³ - 3-а/ 3а = 3( а²+ 3) - а²( 3 - а )/ 3а³ = 3а³+ 9 - а²(3 - а )/ 3а³ = 3а³+ 9 - 3а² + а³/ 3а³ = 9 + а³/ 3а³
б) х /х - 1 + х /х + 1 = х (х + 1)+ х (х - 1) / (х - 1) (х + 1) = х²+х +х²- х /х²- 1 = 2х²/ х²- 1
в) x /x -2x - 4y²/х² - 2xy = x /x -2x - 4y²/x (x - 2y)=x²- 4y²/x (x - 2y)=( x - 2y)(x - 2y) /x (x - 2y) = x + 2y/ x
г) 2a+b - 4ab/ 2a+b = 2a (2a+b) + b (2a+b) - 4ab/ 2a+b = 4a²+ 2ab + 2ab + b²- 4ab/ 2a+b = 4a²+ b²/2a+b