If it's not what You are looking for type in the equation solver your own equation and let us solve it.
a in (-oo:+oo)
-a-1 = 4*a-31 // - 4*a-31
31-a-(4*a)-1 = 0
31-a-4*a-1 = 0
30-5*a = 0 // - 30
-5*a = -30 // : -5
a = -30/(-5)
a = 6
a = 6
| w+9=-4w+29 | | -3k+3=-11+4k | | x+10=6x-45 | | t-2=43+6t | | 5a+2=-3a+10 | | 5n+9=21+3n | | -6+k=-4k-66 | | 8+3m=5m+16 | | -3x+8=-6x-4 | | 6n+6=n+16 | | n+2=-28+7n | | n+1=41+6n | | 7d-7=2d+13 | | -6n+5=2n+77 | | 3n+5=-5n+21 | | -2x-6+1/4x-3=90 | | 4+7d=4d+19 | | -2w+7=3w-3 | | 7t+5=3t+37 | | -8-7n=-6n+3 | | 7t+5=2t+5 | | 3w+4=6w-23 | | -3t+10=6t-89 | | 8+5k=-7k+104 | | 4b+5=5b+10 | | 5w-7=-4w+11 | | 5k+7=-6k+62 | | -6+5a=4a+4 | | 6d+6=-7d+19 | | 4a+5=-2a+53 | | 6x+4=-14+4x | | 5a+3=-29+a |