90 ! выполните действия: 1) (x/2 - x/3) * 5/x^2 2) y^2/4 * (y/5 - 2/y^2) 3) (1/x + 1/y) : 2/xy 4) 12x/x - y * (x/6 + y/6)

1)(3x-2x)×5/6x^2=5x/6x^2=5/6 x 2)y^2×(y^3-10)/4×5y^2=y^3-10/4 3)(y+x)×xy/xy×2=x+y/2 4)12x×(x+y)/(x-y)×6=2x(x+y)/x-y