How do I find the equation of a line between two points?

The equation of a line is written in the form y=mx+c where m is the gradient of the line and c is the y-intercept. These are the two values that we will need to calculate.For example, lets take the two points (2,2) and (6,4). We will label the two coordinates so that (2,2) is no.1 and (6,4) is no.2.To find the gradient, or slope, of the line we use the formula m=(y2-y1)/(x2-x1) where x1 is the x coordinate of no.1 and so on. Therefore, m=(4-2)/(6-2)= 1/2So we can now update our equation y=mx+c by substituting the m value to give y=0.5x+cTo find the c value, or the y-intercept, we then take one of our coordinates (either will work!)So for example, taking no.1, (2,2) and using x=2 and y=2 we can put this into our updated equation y=0.5x+c to give 2=(0.52)+cSolving this for c we get c=1 and then putting this into our equation we get y=0.5x+1 which is the line equation needed.