If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( v )
v = 0
v = 0
v = 0
v in (-oo:0) U (0:+oo)
12/v = 4 // - 4
12/v-4 = 0
12*v^-1 = 4 // : 12
v^-1 = 1/3
-1 < 0
1/(v^1) = 1/3 // * v^1
1 = 1/3*v^1 // : 1/3
3 = v^1
v = 3
v = 3
| 4(3x-5)=-80 | | 16=2(g-12)+2 | | 20+6x-5=9x+21 | | -6(y+8)=-5-8 | | X^5-2x^3-3=0 | | 8f=4+7f | | 3(y-9)+7=10 | | Y=-2x^2-15 | | 9/4y-12=1/4-4 | | 1=2(s-8)-3 | | 2x^3-x-3=0 | | 2(3x-7)=10x-8 | | w-6/2=1 | | 75=9m-24 | | 22-4w=6 | | -26=-x/6 | | (5x-6)=90+3x | | (x^3)+(2y^3)=6 | | 1=z/3-3 | | 1=3k-2 | | 46x-4=-184 | | r/2-(-8)=10 | | X/3-11=20 | | -x/47 | | 2(2x-3)=-6(x+9) | | x^2+42x+5=0 | | 4+2z=12 | | 2(x+6)+3=9+5x | | kx+8=4 | | 66=4w-14 | | 3v-10=47 | | 2x-22=90 |