Math Finding the missing coordinate

Question

The points (- 3, - 4) and (3, r) lie on a line with slope

2/3. Find the missing coordinate.

Answer 1

r=0

(-3,-4) and (3,r)

have a line through them with slope = difference in y coordinates divided by difference in x coordinates

= "rise over run"

= (r- -4)/(3- -3) =2/3

cross multiply

3(r+4) =6(2)

3r+12=12

3r=0

r=0/3 =0