Challenge Your Exam Readiness With Our Free MCAS Practice Questions

MCAS math standards require analyzing quadratic functions using key features. For a quadratic f(x) = ax² + bx + c, the x-coordinate of the vertex is −b/(2a). Here, a = 1 and b = −6, so x = −(−6)/(2·1) = 6/2 = 3. Thus, the vertex’s x-coordinate is 3, answer B. Students can confirm by completing the square: f(x) = x² − 6x − 7 = (x² − 6x + 9) − 9 − 7 = (x − 3)² − 16. In vertex form, f(x) = (x − 3)² − 16, the vertex is (3, −16). The minimum occurs at x = 3 since the parabola opens upward (a > 0). Common errors include using b/2a without the negative sign or mixing up the role of c. MCAS emphasizes multiple representations—graphs, equations, and tables—and connecting them. The vertex gives the function’s extreme value and axis of symmetry x = 3. Understanding vertex form also helps in interpreting transformations from the parent function x², including horizontal shift (to x = 3) and vertical shift (down 16).