If it's not what You are looking for type in the equation solver your own equation and let us solve it.
k in (-oo:+oo)
58 = 3*k+4*k+9 // - 3*k+4*k+9
58-(3*k)-(4*k)-9 = 0
58-3*k-4*k-9 = 0
49-7*k = 0 // - 49
-7*k = -49 // : -7
k = -49/(-7)
k = 7
k = 7
| -1=-5k+6k+8 | | 23+18w=-21+14w | | 121=k+-12 | | -5-2b+4b=19 | | -7t-4+2t=-59 | | -3+d-7d=-51 | | 13=4w-5w+8 | | -2k+3-3k=28 | | 3x-7+5x=17 | | -7+6m-4m=-23 | | 2.75f+w=310 | | 7m+7+5m=-65 | | -119=-7b-4b+2 | | 6a+7-7a=18 | | -6k+2-3k=-25 | | -k+1+4k=16 | | -2t-10-6t=-18 | | k-2+k=10 | | 3(z-3)=7z+4 | | -49=-6m-2m-9 | | -5m-8-4m=-53 | | -2+2t-3t=0 | | 2w+5+5w=82 | | -2=5t-6t-2 | | 42=7w+w-6 | | -n+1+5n=-3 | | 9-a-a=-1 | | -4t-1-3t=13 | | -6-3w-5w=-14 | | -4+x-7x=-28 | | 6=-4a+3a+7 | | 2-7m-3m=-58 |