If it's not what You are looking for type in the equation solver your own equation and let us solve it.
x in (-oo:+oo)
3/4-((5/7)*x) = 503/84-7*x // - 503/84-7*x
3/4-((5/7)*x)-(-7*x)-(503/84) = 0
(-5/7)*x+7*x+3/4-503/84 = 0
44/7*x-110/21 = 0 // + 110/21
44/7*x = 110/21 // : 44/7
x = 110/21/44/7
x = 5/6
x = 5/6
| 4/7+2m=7m-31/7 | | 6+4/5k=2k+168/25 | | -1/5m+7/8=-317/40-m | | -6+6x=7x-11/2 | | t+2/7=5t+66/35 | | 7+5/6k=-3k+37/2 | | 1/2(18m-16)=3(2m+4) | | 9/10-1/3d=2/7d+1181/1890 | | 9-5n=5n+47/3 | | 4-a=1/2a+49/16 | | 2/5d+4/7=65/126+1/3d | | 3/10+1/2k=4/7k+13/35 | | -8+2k=7k-63/11 | | 4/5m+4/5=6m-16/45 | | -1-6m=m+76 | | -1/4d-5=d-55/9 | | 2a-1=3a-1/4 | | 2/5t-5=7t+28 | | 3/4m-10=-1/3m-493/48 | | 1+4m=-4m+73/9 | | -2/7b+3=59/21-1/3b | | -2/5t+1/10=-5/7t+73/70 | | 10+6w=5/7w+317/28 | | -1/2+4a=-a+89/2 | | -1/10-b=b-3/5 | | -7+5w=w-9 | | 9+a=6a-36 | | -1+6d=3/7d-251/56 | | 1/2n-5=-6n-18 | | -6k-5/9=-1595/36+1/4k | | 12-12y=10-10 | | 1/3+4/7w=6w-113/3 |