Explanation

The midpoint between any two points is found by averaging the two points' x-coordinates and their y-coordinates. (This can be proved from the Pythagorean Theorem, which also gives us the distance between two points in the coordinate plane.) The average of 2.5 and 0 is 1.25, so that is the x-coordinate of the midpoint. The average of 3 and -1.5 is . The answer is (A).

Another approach here would be two find the equation of the line in the form . You can determine the slope m from the rise over run between the two points. The y-intercept b is -1.5. Then you could find the point on the line that is halfway along the run, at an x-value of 1.25, and you would find that at that x-value, y = 0.75.

Again, the correct answer is (A).