Find an equation for the straight line connecting point A (7,4) and point B(2,0)

In this question we will use the fact we know a straight line can be written in the form (y-y₁)=m(x-x₁). Where m is the gradient and (x₁,y₁) is a point on the line. We already have a point A so can say x₁=7 and y₁=4 (we could have used point B instead but it won't make a difference)Now we just need to find the gradient of the line. To do this we can use the equation m=(y₁-y₂)/(x₁-x₂) . Subbing in the numbers this gives us m=(4-0)/(7-2)=4/5=0.8
Now we can combine this all to give us the equation of the line as y-4=0.8(x-7). Rearranging gives y=0.8(x-2), the form Edexcel wants.