If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( x )
x = 0
x = 0
x = 0
x in (-oo:0) U (0:+oo)
(4/5)/x = 1 // - 1
(4/5)/x-1 = 0
4/5*x^-1 = 1 // : 4/5
x^-1 = 5/4
-1 < 0
1/(x^1) = 5/4 // * x^1
1 = 5/4*x^1 // : 5/4
4/5 = x^1
x = 4/5
x = 4/5
| 14=m2/3(9y-15) | | 7a+3= | | y=1/2sin(2pix-pi) | | 7m-6-2m^2= | | -2p+5=-2 | | 10y=2x+30 | | 2m^2-5m+3= | | 3(2x+5)=2x-5 | | U-3=1 | | 5n+n=54 | | ln(1/e^2x | | 9m^2+35m-4= | | 12ab-9a-20b+15=0 | | (3x^2+8x^3y)dx+(2y+2x^4)dy=0 | | 4x+10=28 | | 10x-5-4x=6x | | 7m^2+6m-1= | | 0=100+25*t-4.9*t^2 | | 9a-4= | | 1/15÷6 | | -18+3+9=x | | 5+3w=2+9w | | 10-2x=2x+6 | | 5-(3x-10)=12+(x-2) | | 37+9x=5x-11 | | 12ab-9b-20b+15=0 | | 26=q-13 | | 5x+14=32-4x | | x^4+22x^2+121= | | 4x-8=6x-6-3x | | -(19-3x)-(8x+1)=35 | | -4+p=16 |