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-3 = 0
-x-3 = 0
-x-3 = 0
-x-3 = 0 // + 3
-x = 3 // * -1
x = -3
x in (-oo:-3) U (-3:+oo)
(-3*x-4)/(-x-3) = 0
-3*x-4 = 0 // + 4
-3*x = 4 // : -3
x = 4/(-3)
x = -4/3
x = -4/3
| z=3x^3+9xy^3-5x+4y | | (13-b/6)=(2-0.5b/4) | | -2n=8(-6-2n)-8 | | 56+24/6*2 | | 6n-6=8n-2 | | 5y=-5+25 | | x-x^2=90 | | w^2-18w+18= | | x^2-38x+72=0 | | 2=(10+z/-3) | | -3x+18=7(-4x-1) | | 2v^2-32v+128= | | 20/4(6)(6-4) | | 2/3u-1-1/u | | n*5=78 | | t^2+4t+3= | | -2=(3x/5)+1 | | -26+4x=3(x-6) | | 2x+1-5=3 | | 6y=18(1)-6 | | 33+4p=7(3p+1)-8 | | c^2+18c= | | 6y=18(1/3)-6 | | 3-6a=5a-4(3+2a) | | 3-6a=5a-4(3+3a) | | z=3x^2+9xy^2-5x+4y | | s^2+10sg+21g^2= | | 22+b=-3(8b+1) | | 7(b-6)=-32+2b | | 6y=18(0)-6 | | 6+7(8a+3)=27-5a | | 10*10+6*8-(7+3*5)= |