# Math Help - Slope Question! Help Please!

1. ## Slope Question! Help Please!

Find the value of r so the line that passes through each pair has the given slope.

1. (r,3), (5,9), m=2

2. Just use the definition of a slope. Say that we have 2 points $(x_1, y_1)$ and $(x_2, y_2)$.

The slope is given by: $m = \frac{y_2 - y_1}{x_2 - x_1}$

Here: $x_1 = r, \ y_1 = 3, \ x_2 = 3, \ y_2 = 9, \ m = 2$

Plug it all in and simply solve.

3. The gradient of the line, m, is 2. Now remember when we have two points on a line we can find the gradient using this formula:

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

$2 = \frac{3 - 9}{r - 5}$

$\Rightarrow 2(r - 5) = -6$

Now solve for r.