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)/30 = 0
(4*x)/30 = 0
(4*x)/30 = 0
2/15*x = 0 // : 2/15
x = 0
x in (-oo:0) U (0:+oo)
(2*x+2*((3*x)/5))/((4*x)/30) = 0
(16/5*x)/(2/15*x) = 0
16/5*x = 0 // : 16/5
x = 0
x in { 0}
x belongs to the empty set
| (2x+2)/(x)=0 | | (2x+18)/4=11 | | (2x+10)/4=12 | | (2x+1/x-3)-(x-3/x+5)=(-10x+14/x+5) | | 3x-10=2x+7 | | 139000=2795*x+17500 | | (2x+1/3)+(1/4)=(2x-1/6) | | (2x+1/3)(2x+1/3)=0 | | (2x+1/2x-1-1)+(3x+1/3x-2-1)=(3x+2/3x-1-1)+(6x+1/6x-5) | | (2x+1)x-1/2=0 | | (2x+1)/x+x/(2x+1)=58/21 | | (2x+1)/7-(3x+2)/14=x | | (2x+1)/5=6x | | (2x+1)/5=(x-4)/2 | | (2x+1)/5=(x+2)/4 | | (2x+1)/3x=0 | | (2x+1)/3=(x+6)/2 | | (2x+1)/3=(6x-9)/5 | | (2x+1)/3+16=3x | | (2x+1)/(5x-7)=3/4 | | (2x+1)/(4x+1)=1/3 | | (2x+1)/(3x-4)+(5/7)=1 | | (2x+1)/(3x)=0 | | (2x+1)/(1/3)+(x-1)/(4)=(13/2) | | (2x+1)*(x-1/2)=0 | | (2X+1)(X-1/2)=0 | | (2x+(3)/(5))(4x-(10)/(7))=0 | | (2x)/5=X+4/3 | | (2x)/4+2=6x | | (2x)/3=4 | | (2x)/3=15 | | (2x)/3+9=-7 |