What is the equation of the line which includes points (1, 3) and (2, 8)?

The equation will be like this: y=ax+c. a is the slope and c is where the line crosses the (vertical) y axis - AKA the y-intercept.As for the slope, it can be found like [(8-3)/(2-1)]. That gives 5. Another way to see it is to notice that between (1,3) and (2,8), the line moved up 5 points and went to the right only 1. And for the y-intercept, make the equation y = 5x + c. Solve for c by filling x and y with information from any of the two points. Let's choose (1,3). Plugging in gives the equation 3=5(1)+c. C equals -2. So, the final equation is:y = 5x - 2