If it's not what You are looking for type in the equation solver your own equation and let us solve it.
b in (-oo:+oo)
6/13-((3*b)/13) = 8/13 // - 8/13
6/13-((3*b)/13)-(8/13) = 0
(-3/13)*b+6/13-8/13 = 0
-3/13*b-2/13 = 0 // + 2/13
-3/13*b = 2/13 // : -3/13
b = 2/13/(-3/13)
b = -2/3
b = -2/3
| 64285714y=42857143 | | -5+1=-10 | | 0.8p=16 | | -0.2(-1+3u)= | | 10=x/4-3 | | 0.8=16 | | t--15=21 | | 916=.75h | | 6x+7=6(x+8) | | 6-8-3=30 | | 7x^2+51x+4=0 | | 4+(w+-6)= | | As+3b=2f | | t=rd | | 5x+12((12x-65)/5)=13 | | 3x(4-2)= | | 1.5x+1=7 | | (4u^4*y^6-16v^3*y^3)/12y^4 | | 3x/6=6/12 | | log[6](5x-7)=2 | | 12-x/-4=5x-7/3+2 | | 2.3x=67 | | 6x=-41 | | 3w+2=17+7w | | -3x-1=-(4x-4) | | -11y-11=9-8y | | a+11=200 | | X/3=-7/4 | | -94=2(5b-7) | | -5+(4+z)= | | b-25=55 | | 21=-(t+82) |