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)
-643/252 = (5/7)*k+3*k+3/4 // - (5/7)*k+3*k+3/4
-((5/7)*k)-(3*k)-643/252-(3/4) = 0
(-5/7)*k-3*k-643/252-3/4 = 0
-26/7*k-208/63 = 0 // + 208/63
-26/7*k = 208/63 // : -26/7
k = 208/63/(-26/7)
k = -8/9
k = -8/9
| 133/5=d+3/5d+9 | | 199/56=7w-3/4w+3/7 | | -4/5k+7/9+k=149/180 | | -2/3d+8/9-5/6d=-65/18 | | -1+1/7m-2/3m=-17/28 | | -14/33=3m-6m+2/3 | | -x^2+36x-87=0 | | x+8/9+4/5x=-1/9 | | -2/5a-1-4a=-21/5 | | 7d-1/2+6d=207/2 | | 51/35=3d-6d+3/5 | | -1=-3t-1/2t-1 | | -4/5a+2/7-3/4a=337/420 | | 5+k+4k=19/2 | | 1+1/6a+2a=41/2 | | -5t-3+6/7t=95/7 | | 59/10=-1/2d-2/5d+5 | | 3/7n-8-6n=-470/49 | | -828/35=5/7d+5d-4/5 | | 6+4/5k-4k=-66/5 | | 5/8-2/3m+7m=-443/264 | | -5/7t-5/9-6/7t=-5/9 | | 2/9+6x+5x=-1087/9 | | 7/8-5b+4b=-81/8 | | 2(x^2+2x)=96 | | 18=5m-1/3m+4 | | 7w-2/5+3w=548/5 | | 4/7k+2-2/3k=121/63 | | 124=6n+5n+3 | | 5d-1/10-3/4d=163/70 | | 4k-9/10+2k=-9/10 | | 10=-2d+5d+10 |