Question

2.

Fit a quadratic function to these three points:

(−2, 8), (0, −4), and (4, 68)

A. y = −2x2 − 2x − 4

B. y = 4x2 + 2x − 4

C. y = −4x2 − 2x − 4

D. y = −2x2 + 2x − 4

Answer 1

B

Explanation:

just put the x and y values into the equations and see which equation stays true.

for example, point (4, 68) rules out A and C even without detailed calculation, because these 2 expressions can produce for positive x only negative y (and 68 is clearly a positive y).

so, when using this point in B :

68 = 4×4² + 2×4 - 4 = 4×16 + 8 - 4 = 64 + 8 - 4 = 68

correct.

and it is correct also for the other points.

so, B is the right answer.

Answer 2

It's C.

Explanation: