First, find the gradient/slope: Use slope formula: m=(y2-y1)/(x2-x1) =(11-5)/(3-1) =6/2 =3 Then use the line equation formula: y=mx+c You can substitute (1,5) if you like, also must substitute the slope as well! 5=3x1+c c=2 Then find the full equation, which gives you the answer: y=3x+2