If it's not what You are looking for type in the equation solver your own equation and let us solve it.
d in (-oo:+oo)
81 = 7*d+d-7 // - 7*d+d-7
7-(7*d)-d+81 = 0
7-7*d-d+81 = 0
88-8*d = 0 // - 88
-8*d = -88 // : -8
d = -88/(-8)
d = 11
d = 11
| -8x+5=-67 | | -15=-7w+5w-3 | | 64=2k+3k+9 | | 36=-2m+6m+8 | | 4t+10+5t=64 | | -4=-3m+6m-7 | | 23=t+6t+9 | | -8+4m+m=27 | | 10+6w+6w=142 | | t-3+t=7 | | -10=-6n+4n-6 | | -17=-5k+k-5 | | 9-6b+b=14 | | 10-3b+2b=-1 | | 10+7w+6w=114 | | 79=-4d-4d+7 | | -1=m-2m+1 | | 10-5x-x=40 | | 15=-3a+5a+9 | | 10-6w+5w=2 | | -6-n+2n=-14 | | 6=5t-2t-9 | | z=a+blnx | | -3=-4w+2w+9 | | 9-7k+k=-33 | | -22=2n+4n+2 | | -7b-7+3b=1 | | 6n-8-n=47 | | -9+2t+6t=71 | | 7n+8+3n=-2 | | 3w+5+5w=93 | | -10+7b+7b=32 |