If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( x )
4-x = 0
4-x = 0
4-x = 0
4-x = 0 // - 4
-x = -4 // * -1
x = 4
x in (-oo:4) U (4:+oo)
(5*x-7)/(4-x) = 0
5*x-7 = 0 // + 7
5*x = 7 // : 5
x = 7/5
x = 7/5
| y^4-y^3-y^2+y=0 | | 10x+20=3x+167 | | x/6+8=15 | | y^4+4y^2=0 | | 5a-15/3-a | | 4-3x=x+6 | | y^4-2y^2+1=0 | | -4/2=-3/2t | | 2x-9=5x-3 | | -1/2+5/2 | | -4x+5=10 | | 12+1(x+3)=10 | | 4x-=2x+2 | | 12x-9=8x-36 | | 8x+9=2x+49 | | h(t)=-16t^2+112t+8 | | -1/2=-3/2t-5/2 | | 3x^2+12=312 | | 9x+7y-8z=-20 | | 8x-16=6x+5 | | -6x-1g(x)=4x^2 | | P(63000)=10x-2000 | | 1/3(10x-3)=7 | | 5y+5x+12 = 0 | | y^5-3y^4+3y^3-3y^2+2y=0 | | 8x*2=32 | | 2x+5+6=-27 | | y=x^2+8x+20 | | 6y+2y=7y-4 | | 3/3x-9+x-2/3-x | | y^6+3y^2-1=3y^4 | | y=1.32x^2+17 |