**1. Does a horizontal line have a gradient?**

Yes, the gradient of a

horizontalline is 0.The gradient of a

verticalline is undefined. i.e. It cannot be found.

**2. How can you tell whether a function has a straight line graph?**

In the formula for the function , the x variable and the y variable are

bothto the power of1and all terms are being added and/or subtracted. e.g 3x + 4y = 3

**3. What does it mean if there is no constant term in a linear function e.g. y = 3x?**

The straight line graph of the function passes through the origin (0, 0).