If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( z )
z = 0
z = 0
z = 0
z in (-oo:0) U (0:+oo)
18/z = 1 // - 1
18/z-1 = 0
18*z^-1 = 1 // : 18
z^-1 = 1/18
-1 < 0
1/(z^1) = 1/18 // * z^1
1 = 1/18*z^1 // : 1/18
18 = z^1
z = 18
z = 18
| Y=3.4+.8y+1.5-.5r+4-4-.2r | | -6.5v+6.4=-22.2 | | 2.79/100 | | X-2.6+x=8.2 | | y/18=1 | | 9x^2+3x^3= | | 2y-3=38 | | -10(s+5)=-42 | | 0987654321+1234567890= | | (x+2)=24 | | 6*(7+2)=(6*7)+(t*2) | | 3b+5c=15 | | 2h-6=5h-9 | | a(x+2)=24 | | 5(d+3)=2d-6 | | Y=3/2x,6x-4y=1 | | 2x-23y=7 | | 125=65+4n | | g(x)=2x+9 | | 9m-23=-63+4m | | 5/9x2/7 | | u=v+14whatisv | | a^2+5a+10=3a+-6 | | X+14=4x+16 | | 4w+5=5w+12 | | 15x-8=11x-24 | | 2/3x=6. | | 12x+21=10 | | 4(3z+2)-7x= | | 10x-35=-11 | | X^3-(3x)=0 | | 5/(3x^2y)-4/6xy^3 |