If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( r )
r = 0
r = 0
r = 0
r in (-oo:0) U (0:+oo)
35/28 = 24/r // - 24/r
35/28-(24/r) = 0
35/28-24*r^-1 = 0
-24*r^-1 = -5/4 // : -24
r^-1 = 5/96
-1 < 0
1/(r^1) = 5/96 // * r^1
1 = 5/96*r^1 // : 5/96
96/5 = r^1
r = 96/5
r = 96/5
| -2d=4d-43 | | -7b-11b= | | 3.5/8=a/3.2 | | 0.12(0.06)= | | 17d-6=-15 | | 17d-6=-13 | | 3+6p-p=6p+8 | | 1-x+1= | | -4.5x+12.3=23.7 | | 10+3x=5g | | 6/2=c | | x^2-11x+20.25=0 | | V/8=24.5 | | 25x^5y^2-512xy^2=0 | | h/15=16/3 | | 5.50h=22 | | 4x^2+x^4-21=0 | | 1.8=3y+16.2 | | B-1/4=3.5 | | 13=3x+7x-7 | | 6(3s+7)=168 | | 2+x-(3-2x)= | | 2w-8=-19 | | 9=-6(2x-3)+15 | | 3+5x=4x+6 | | 12-8=-52 | | 3n+2.1=5.7 | | 4(2l+5)=133 | | 5x-5=7x-9 | | 5x+20+40=25 | | 9x-1=10y-4 | | 4x-21+6x=49 |