So we know the lines are parallel.
Thus, the equation should look something like this:
y = 5x + b
Now, we have to solve for b.
Plug x=1 and y=2 into the equation to solve for b
2 = 5 + b
Subtract both sides by 5
-3 = b
b = -3
Plug that value into the equation.
y = 5x - 3
That's your answer.
Have an awesome day! :)