Question

What is the answer to this question?

Answer 1

Answer:

Quadratic: y = -x^2 + 7

Step-by-step explanation:

Diff                       Diff         Diff in

in x     x       y       in y         Differences

         -2      3

1        -1       6       3

1         0      7        1               -2            

1         1       6       -1               -2

1         2      3       -3               -2

The differences in x are all 1. The differences in y are not equal, so it is not linear. The differences in the differences in y are all 2. It is quadratic.

Try: y = -x^2 + 7

x = -2:

y = -(-2)^2 + 7 = -4 + 7 = 3

You get (-2, 3) which is a given point.

Now try the same x value with the other quadratic equation.

y = x^2 + 7

x = -2:

y = (-2)^2 + 7 = 4 + 7 = 11

You get (-2, 11) which is not a given point.

Answer:

Quadratic: y = -x^2 + 7