Make a table and a graph for each function. Use only positive values for x in exercise 28.

26. y=2x^2-4

28. y=7/x

wolframalpha.com is your friend. For #26, see

http://www.wolframalpha.com/input/?i=table+2x^2-4+for+x+%3D+-3+..+5

To make a table and a graph for each function, we'll need to plug in different positive values for x and calculate the corresponding y-values.

26. y = 2x^2 - 4:

Let's choose four positive values for x, such as 1, 2, 3, and 4. Then we'll calculate the corresponding y-values using the equation.

For x = 1:
y = 2(1^2) - 4 = 2 - 4 = -2

For x = 2:
y = 2(2^2) - 4 = 8 - 4 = 4

For x = 3:
y = 2(3^2) - 4 = 18 - 4 = 14

For x = 4:
y = 2(4^2) - 4 = 32 - 4 = 28

Now, we can create a table:

| x | y |
|-------|-------|
| 1 | -2 |
| 2 | 4 |
| 3 | 14 |
| 4 | 28 |

To create a graph, we plot the x-values on the x-axis and the corresponding y-values on the y-axis.

The graph for the function y = 2x^2 - 4 will look like a "U" shape, opening upwards, with the vertex at (0, -4).

28. y = 7/x:

Similarly, let's choose positive values for x, such as 1, 2, 3, and 4, and calculate the corresponding y-values.

For x = 1:
y = 7/1 = 7

For x = 2:
y = 7/2 = 3.5

For x = 3:
y = 7/3 ≈ 2.333

For x = 4:
y = 7/4 ≈ 1.75

Now, we can create a table:

| x | y |
|-------|---------|
| 1 | 7 |
| 2 | 3.5 |
| 3 | 2.333 |
| 4 | 1.75 |

To create a graph, we plot the x-values on the x-axis and the corresponding y-values on the y-axis.

The graph for the function y = 7/x will start at a high value and gradually decrease as x increases. It will approach the x-axis but will never touch it, as x cannot be zero. The graph will have a vertical asymptote at x = 0, indicating that the function is undefined for x = 0.