If it's not what You are looking for type in the equation solver your own equation and let us solve it.
m in (-oo:+oo)
m-3*m+1 = 13 // - 13
m-3*m-13+1 = 0
-2*m-12 = 0 // + 12
-2*m = 12 // : -2
m = 12/(-2)
m = -6
m = -6
| 7-3m+2m=13 | | -4b+1+6b=-5 | | -4+2m-6m=20 | | 7a+3+2a=66 | | -5+6d+2d=-5 | | 9+7t-t=9 | | -2-2b+3b=3 | | 9+3d-6d=-12 | | -4w+4+7w=10 | | -3x+3+6x=-33 | | -33=3b+5b+7 | | 2+6n-2n=-6 | | 2+4a-2a=-2 | | 7x-8+3x=12 | | 7m-9+6m=134 | | 37=-7m-7m+9 | | -2+2a-5a=-14 | | 7b-5+6b=151 | | 19=3w-4w+9 | | -70=-3n-3n+2 | | 7x-3+4x=-36 | | 8+6b+b=57 | | (48-x)+11=(x+11)/4 | | -24=3k+7k+6 | | 8+4m+3m=15 | | 7b+2+6b=145 | | -4d+1+5d=2 | | 4+7w+2w=67 | | -1=-5m+2m-1 | | -3a+2+a=-6 | | 10=-7n+6n-2 | | -11=4x-x+7 |