The problem asks us to find the gradient (slope) of a line given two points on the line: $(12, 72)$ and $(5, 9)$.

1. Problem Description

The problem asks us to find the gradient (slope) of a line given two points on the line: $(12, 72)$ and $(5, 9)$.

2. Solution Steps

The formula for the gradient $m$ of a line passing through two points $(x_1, y_1)$ and $(x_2, y_2)$ is:

$m = \frac{y_2 - y_1}{x_2 - x_1}$

Let $(x_1, y_1) = (12, 72)$ and $(x_2, y_2) = (5, 9)$. Then, we have:

$x_1 = 12$, $y_1 = 72$

$x_2 = 5$, $y_2 = 9$

Substitute these values into the gradient formula:

$m = \frac{9 - 72}{5 - 12}$

$m = \frac{-63}{-7}$

$m = 9$

3. Final Answer

The gradient of the line is 9.