Im currently working on this for my AS-Level Maths, and im completele stuck on finding the equation of a straight line! My book explains it about as well as a cow explains calculus to a baby!

Here for example is one of the questions...

Find the equation of...

(i) parralel to y = 2x and passing through (1,5);

all my book is telling is useless because i always end up with the question!!!!!!!

if someone could explain to me the steps needed to find the equation of this line, i would be very gratefull!!
thanks