Find the value of y so that the points (-5,10) and (3,y) lie on a line with slope -3/8

Find the value of y so that the points (-5,10) and (3,y) lie on a line with slope -3/8

$$slope = \frac{\Delta y}{\Delta x} = \frac {y-10} {3-(-5)} = \frac {y-10} {8} \\\\ \text{also slope } = -\frac{3}{8}$$

 

$$so\ we\ have \quad \frac{y-10}{8} = -\frac{3}{8} \qquad or\ \quad y-10=-3$$

 

the value of y = 7

$$slope=\frac{y_a-y_b}{x_a-x_b}=\frac{y-10}{3--5}=\frac{y-10}{8}=-\frac{3}{8}$$

 

Now solve for y.

 

Good luck! :)