Question

Determine whether the function is linear. If it is, identify the rate of change. X -7, -5, -3, -1, 0 Y 11, 14, 17, 20, 23​

Answer 1

Answer: Yes;

Explanation: The function is linear in that the X values are increasing by 2 and the Y values are increasing by 3.

Answer 2

Not linear

Explanation:

X | -7 | -5 | -3 | -1 | 0

Y | 11 | 14 | 17 | 20 | 23

-5 - (-7) = +2

14 - 11 = +3

-3 - (-5) = +2

17 - 14 = +3

-1 - (-3) = +2

20 - 17 = +3

0 - (-1) = +1

23 - 20 = +3

There is a linear function graphed that would pass through the first 4 points, but not the last one;

You can discern this as there is a common pattern we can identify, everytime the x-value increases by 2 the y-value increases by 3, except with the last coordinates;

The rate of change, also known as the gradient, is the change in x divided by the change in y (Δx/Δy);

In the case of the first 4 points, the rate of change would be 3/2 or 1.5;

This simply means when x increases by 1, y increases by 1.5, IF the function is linear;

However, as mentioned the last point doesn't fit the pattern;

There, we can see the y-value increases by 3 when the x-value only increases by 1;

This means the point (0, 23) isnt on the graph of the function, the points (0, 21.5) and (1, 23), on the other hand, would be.