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)
(x-25.56)/x = 40.6 // - 40.6
(x-25.56)/x-40.6 = 0
(x-25.56)/x+(-40.6*x)/x = 0
x-40.6*x-25.56 = 0
-39.6*x-25.56 = 0
(-39.6*x-25.56)/x = 0
(-39.6*x-25.56)/x = 0 // * x
-39.6*x-25.56 = 0
-39.6*x-25.56 = 0 // + 25.56
-39.6*x = 25.56 // : -39.6
x = 25.56/(-39.6)
x = -0.64545455
x = -0.64545455
| 28+25+x=1.55x | | 5(x-7)=5(2) | | 46+25+x=1.45x | | 50+25+x=1.55x | | (x-y)/x=40 | | 2(5-b)=2-4b | | 21+25+x=2x | | x-x(3/4)=165 | | 21+25+x=3x | | 3k=-2(7+k) | | 3/9x=12 | | F(n)=2n^2-5 | | 2y^3+7y^2+21y+9=0 | | 2y^3-7y^2+21y+9=0 | | x+4y=60 | | (A^4b^5/ab^4) | | 9(b+10)=5b | | 8n-(6n-5)=3 | | C=0.13 | | 7x-2=2y | | 6x-5=3+25 | | Log[5](6x-3)=2 | | 5x+3-3x=8 | | ln(7x+4)=ln(2x-21) | | 0.2z=0 | | b-7+2b= | | 8x+49=5(x+5) | | -7x=12-8 | | B-7+2B=18 | | -2(2x+9)=2 | | x-5x-17=11 | | -5n+9n+6= |