Question

A parabola passes through the points (-2,8), (0,2), and (1,5). What function does the graph represent? A. f(x) = -2x2 + x + 2 B. f(x) = 2x2 + x + 2 C. f(x) = 2x2 + x − 2 D. f(x) = 2x2 − x − 2

Answer 1

Answer:

B

Step-by-step explanation:

To select the correct equation, check to see that the c term of $ax^2+bx+c$ is 2 since the y-intercept is (0,2). This means only A and B are options since C and D have -2.

For A and B, substitute the other two points (-2,8) and (1,5) into the equations and see if it hods true.

$A. f(-2) = -2(-2)^2+(-2)+2 = -8-2+2=-8$

This is not 8 and is not true.

$B. f(-2) = 2(-2)^2+(-2)+2 = 8-2+2=8$

This is true. This is the solution.