Find x if the slope between (2,1) and (x,9) is 2

Recall the slope (m) when given two points, (x_{1}, y_{1}) and (x_{2}, y_{2}), is defined by the following formula:

Slope = m = (y_{2} - y_{1}) / (x_{2} - x_{1} )

You are given the following:

m = 2

(x_{1}, y_{1}) = (2, 1)

(x_{2}, y_{2}) = (x, 9)

This means you are looking to solve for x_{2} in the slope formula. To do so, plug in the given values for slope and the two points into the formula:

2 = (9 - 1) / (x_{2} - 2)

2 = (8) / (x_{2} - 2)

After we cross multiply, we get the following:

2·(x_{2} - 2) = 8

Now we divide both sides of this equation by 2:

(2·(x_{2 }- 2))/2 = 8/2

x_{2
}- 2 = 4

Adding 2 to both sides of the equation, we solve for x_{2} :

x_{2} - 2 + 2 = 4 + 2

x_{2} = 6

Thus, for the point (x, 9), x = 6.

## Comments

nice explanation, Tamara! :)