Second grade mathematics to determine the function expression There are two points a (0,3) and B (4,1) on the image of the function. Find the expression of this linear function.

Second grade mathematics to determine the function expression There are two points a (0,3) and B (4,1) on the image of the function. Find the expression of this linear function.

The linear slope k = (1-3) / (4-0) = - 0.5, and the linear equation is y = - 0.5x + B. according to the coordinates of point a, we know that the longitudinal intercept of the line is 3, that is, B = 3. So the linear equation is y = - 0.5x + 3