Problems 142–151 are based on previously learned material. The purpose of these problems is to keep the material fresh in your mind so that you are better prepared for later sections, a final exam, or subsequent courses such as calculus.

Suppose f (x) = x² + 2x − 3.

(a) Graph f by determining whether its graph is concave up or concave down and by finding its vertex, axis of symmetry, y-intercept, and x-intercepts, if any.

(b) Find the domain and range of f .

(c) Determine where f is increasing and where it is decreasing.