Your equation would be y = -3x + 2.
A property of parallel lines is that they all have the same slope, which means that as the slope of y = 5 - 3x is -3 (because it is attached to the x), the slope of the parallel lines must also be -3.
You can finish the equation by seeing that the point they have given you is on the y axis, as x is 0, and so it is the y intercept for this line. This means that your final equation is y = -3x + 2.
I hope this helps