If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( x )
3-x = 0
x+3 = 0
3-x = 0
3-x = 0
3-x = 0 // - 3
-x = -3 // * -1
x = 3
x+3 = 0
x+3 = 0
x+3 = 0 // - 3
x = -3
x in (-oo:-3) U (-3:3) U (3:+oo)
(x-12)/(3-x) = (x+33)/(x+3) // - (x+33)/(x+3)
(x-12)/(3-x)-((x+33)/(x+3)) = 0
(x-12)/(3-x)+(-1*(x+33))/(x+3) = 0
((x-12)*(x+3))/((3-x)*(x+3))+(-1*(x+33)*(3-x))/((3-x)*(x+3)) = 0
(x-12)*(x+3)-1*(x+33)*(3-x) = 0
2*x^2+21*x-135 = 0
2*x^2+21*x-135 = 0
2*x^2+21*x-135 = 0
DELTA = 21^2-(-135*2*4)
DELTA = 1521
DELTA > 0
x = (1521^(1/2)-21)/(2*2) or x = (-1521^(1/2)-21)/(2*2)
x = 9/2 or x = -15
(x+15)*(x-9/2) = 0
((x+15)*(x-9/2))/((3-x)*(x+3)) = 0
((x+15)*(x-9/2))/((3-x)*(x+3)) = 0 // * (3-x)*(x+3)
(x+15)*(x-9/2) = 0
( x+15 )
x+15 = 0 // - 15
x = -15
( x-9/2 )
x-9/2 = 0 // + 9/2
x = 9/2
x in { -15, 9/2 }
| (x^4)+(-10x^2)+(9)=0 | | x+3x+17=109 | | 20c=398 | | 8x-9=4x-7 | | 398c=20 | | 100=-5x | | 4x+2y=-3 | | 2x+65=6x+9 | | 3x-24=x+4 | | -7.3-5.18=-51.9 | | 4(4w+5)+3w=8(w+7)-3 | | 3x^3-51x=0 | | 20c=183 | | 22=2(4a+2) | | 20c=89 | | 5x+3-2x+11=x-6+x+14 | | 183w=4 | | -3x+1=-26 | | x^4-6x^2=-4 | | 4c=89 | | -3(7-2y)=-14-1 | | .05x+10(200-x)=.45x | | (x^4)+(-10x^2)+(16)=0 | | 2(y-3)=4x | | -1(8m+4)=4m-2(6m+2) | | -2x+7=2 | | (x^4)-(12x^2)+(11)=0 | | 0.5y+1=4x-2 | | 2x-5y=28 | | -5(x+4)=7-(-5) | | (3+2i)(4+3i)= | | -3x+8=2x+3 |