First, you have to isolate your y in the first equation:
6x - 3 = 7y
7y = 6x - 3
y = 6/7 x - 3/7
Then, since the line is parallel to the first one, you keep the slope. the only thing that changes is the b. To find that, you plug in the point given:
8 = 6/7 (-2) + b
Then solve for b:
8 = -12/7 + b
b = 8 + 12 /7
b = 68/7
Last, you put it back in the first one:
y = 6/7 x + 68/7