Remember the equation of a line: y=mx + b where m is the slope and b is the vertical offset of the line.
So a line parallel to the equation will have the same slope (m) but a different (b).
The new equation will be y=6/7x + b.
To find b, plug in (3,4) x=3 and y=4 to find the new b since (3,4) is on the new line.
Solve 4=6/7*3 + b
b = 4 - 6/7*3