Gradients of lines can be positive, negative, zero or infinite.

**Positive Gradients**

The lines shown in red below all have positive gradient.

They slope from bottom left to top right.

**Negative Gradients**

The lines shown in blue below all have negative gradient.

They slope from top left to bottom right.

**Zero Gradient**

The lines shown in green below all have zero gradient.

They lie flat or horizontal and are parallel to the x-axis.

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**Infinite Gradient**

The lines shown in orange below all have infinite gradient.

They are vertical and are parallel to the y-axis.