If it's not what You are looking for type in the equation solver your own equation and let us solve it.
x in (-oo:+oo)
y-(((3/7)*x^21)/y)-3 = 0
y+(-3/7)*x^21*y^-1-3 = 0
-3/7*x^21*y^-1 = -(y-3) // : -3/7*y^-1
x^21 = -7/3*y*(3-y)
x^21 = -7/3*y*(3-y) // ^ 1/21
x = -(7/3)^(1/21)*y^(1/21)*(3-y)^(1/21)
x = -(7/3)^(1/21)*y^(1/21)*(3-y)^(1/21)
| y+3y-y=20+y | | 3-5d=4d-2-10d | | B-2ac=0 | | 5a+8a-a= | | 2c-12=-18 | | -c+10=-10+9c | | 3(z+3)=18 | | 2x^3-6x^2+5x+2=0 | | 6d=2(4+3d) | | -4m=4-6m | | 3x-3x+6=5 | | -2r+-13r-17r+2=-12 | | 27x+5=28x+2 | | 7x-3=-3+6x | | 4r+9=3+10r | | a+3b=4c | | 2v-5=1 | | x=35+460x-5x^2 | | 9.00=0.5(x)+5.32 | | 2d-d=17 | | (-1+-1u)(3+-2u)=0 | | (4m^3n^4/3mn)^3=0 | | 6.82=0.5(x)+5.32 | | 88.56+5x=9.76 | | 6.82=0.5(x)5.32 | | 3cos^2x-2cosx-4=0 | | R=35+460x-5x^2 | | (4m^3n^4/3mn)^3 | | 142+10x=46+22x | | (K+9)=71 | | 0=-16t^2+22t+5 | | 14x-16x=10x |