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/40 = 0
x/40 = 0
x/40 = 0
1/40*x = 0 // : 1/40
x = 0
x in (-oo:0) U (0:+oo)
7 = 960/(x/40) // - 960/(x/40)
7-(960/(x/40)) = 0
7-38400*x^-1 = 0
-38400*x^-1 = -7 // : -38400
x^-1 = 7/38400
-1 < 0
1/(x^1) = 7/38400 // * x^1
1 = 7/38400*x^1 // : 7/38400
38400/7 = x^1
x = 38400/7
x = 38400/7
| 5z+4=18 | | 14x^2-141x+10=0 | | -5+3(5x-13)=51 | | 138.75=9.25(-6+v) | | y-9=-9(X+1) | | 1-8n=11-7n-3n | | 10k+10=6k-10 | | 6x+58+9x=87 | | 7=900/(x/40) | | 0=7x-12 | | 10(6p+5)=-5(3p+91) | | -7x+3=2x-6 | | 4t^2-15t+12=0 | | 16=1/9x^2 | | 10m-2.5=9.35 | | 2x+9-6x=14 | | 3u+2u=1 | | y=4x+2-3 | | -5x+5(-4x-12)=190 | | 8/3c-2=2/3c-2 | | 2j-8=2 | | 2x+6=3x+10 | | 50+h=310 | | 2[c+4]+8=10 | | 1x-5x=17 | | 31.4=2(3.14) | | 6x-6(2x+11)=-30 | | y=-4x+2-6 | | x=x^2-7x-8 | | 2/3x10/6 | | 18x-5-16x=16x+3-16x | | 2x+1b=2b |