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)
(-4/7)*a-((1/2)*a)+8/9 = 2/63 // - 2/63
(-4/7)*a-((1/2)*a)+8/9-(2/63) = 0
(-4/7)*a+(-1/2)*a+8/9-2/63 = 0
6/7-15/14*a = 0 // - 6/7
-15/14*a = -6/7 // : -15/14
a = -6/7/(-15/14)
a = 4/5
a = 4/5
| -3/8-7a+a=103/24 | | 8+4m-5/6m=257/6 | | 2/7m-1/9+3/5m=2197/315 | | 5/6d-7+d=-7 | | -89/54=2b+2/3b-1/6 | | 14=4x+4x+6 | | 125=6a+7a+8 | | 1-2a+2/7a=1 | | -5/7+7n+2/3n=-176/21 | | 4d+3+2/5d=147/5 | | N/7=9 | | -3/7+4d-6d=-143/7 | | -3/4n+1/3+6n=1/3 | | 3+1/6t+4t=-31/48 | | 55=-5k+2/3k+3 | | 4x-7-6x=-19/3 | | 4/5t-7+3t=117/5 | | 1+3n+6n=-17 | | 3-5t-7t=-69 | | 2+t+4t=7 | | -19/2=-2k+3k+1/2 | | 3+a+a=9 | | -6d+1-2d=13/5 | | 2/3+2/5k-3k=2/3 | | -17/3=w-1/6w-2/3 | | 6=-t+2/3t+9 | | 4/5t-1+6t=25/9 | | 5b+3/4+5/6b=213/4 | | 4d+1/10+5/7d=3307/70 | | 1/3-3m+3/4m=113/96 | | 2+6x+7x=17/2 | | 1/4+7x+6x=365/4 |