Answer:
Refer to the step-by-step explanation.
Explanation:
Below are the solutions to your given questions.

6) To graph the equation 'y = −3', simply draw a horizontal line at y = -3 on the coordinate plane. See the attached image.

7) To graph the equation 'y + 4 = 0', start by rearranging the equation:
⇒ y + 4 = 0
∴ y = -4
To graph, simply draw a horizontal line at y = -4 on the coordinate plane. See the attached image.

8) Given the equation, 'y = x + 3'. Simply plug in the given x-coordinates to find the y-coordinate.
When x = 7:
⇒ y = 7 + 3
⇒ y = 10
∴ (7, 10)
When x = -4:
⇒ y = -4 + 3
⇒ y = -1
∴ (-4, -1)
When x = 0:
⇒ y = 0 + 3
⇒ y = 3
∴ (0, 3)
Thus, our points are: (7, 10), (-4, -1), and (0, 3). Plot these points in the coordinate plane. Then, using a straight edge connect the three points. See attached image.

The formula to find the slope (m) between two points (x₁, y₁) and (x₂, y₂) is:

In our case, let's define:
- (x₁, y₁) → (2, -6)
- (x₂, y₂) → (4, -12)
Plugging in the given points:

So, the slope of the line that passes through the points (2, -6) and (4, -12) is -3.