If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( p )
4-p = 0
4-p = 0
4-p = 0
4-p = 0 // - 4
-p = -4 // * -1
p = 4
p in (-oo:4) U (4:+oo)
(10*p-40)/(4-p) = 0
10*p-40 = 0 // + 40
10*p = 40 // : 10
p = 40/10
p = 4
p in { 4}
p belongs to the empty set
| 7z-6=8 | | 7+3x-2=7 | | 4b+5=2b+6 | | 21z+5=28z+2 | | ((x*x*x*x*x*x)-64)=0 | | 3=z/7.8 | | 8-4x=-2x+2 | | ((x*x*x*x*x)-32)=0 | | -5(x+1)=-5-5x | | 12v^2+6v-8=-4 | | 4a-2whena=6 | | (x-2)180=3240 | | (x-2)180=2160 | | 5x-3y=58 | | 9=-3e+6 | | -39=3x+3 | | Y=4-3-2 | | 4c+8c= | | Y=433-2 | | x+780=975 | | 7y+4.5=32.5 | | x^4+3x^2-10x+26=0 | | S^2-7s+14=20 | | -12=4f-24 | | 4x+7y=1036 | | -4(x+2)=-4(-2-x) | | 2*(x+2)=x+3 | | (x-0.5)*(0.2+x)=0 | | 3=3(x-3)+5-2x | | 50*1x=180 | | 4b+7-3b= | | 50*1x=30 |