Mathematics - PearsonAccess.com

Objective 1Does the graph below represent the equation y 2x 2 4?y8642(1, 2)–4 –3 –2 –1 0 1 2 3 4–2–4(2, –4)x–6–8–10–12–14–16(3, –14)–18●●Verify that the equation and the graph both describe the sametype of function. The equation y 2x 2 4 is a quadraticfunction because there is an x 2 term in the equation. The graphis a parabola. It describes a quadratic function. Both theequation and the graph describe a quadratic function.Check several points on the graph to see whether theircoordinates satisfy the equation y 2x 2 4. Choose pointswith coordinates that are easily read from the graph. In thiscase, choose the points (3, 14), (1, 2), and (2, 4).Substitute these values into the equation y 2x 2 4 anddetermine whether the equation is true.Point ( 3, 14) Point ( 1, 2) Point ( 2, 4) x 3 and y 14 x 1 and y 2 x 2 and y 4y 2x 2 4 y 2x 2 4 y 2x 2 414 2(3) 2 4 2 2(1) 2 4 4 2(2) 2 414 2(9) 4 2 2(1) 4 4 2(4) 414 18 4 2 2 4 4 8 414 14 2 2 4 4The coordinates of the points (3, 14), (1, 2), and (2, 4)satisfy the equation.20