For this case we have that by definition, the pendeinte of a line is given by:
[tex]m = \frac {y_ {2} -y_ {1}} {x_ {2} -x_ {1}}\\(x_ {1}, y_ {1}) :( 3, y)\\(x_ {2}, y_ {2}) :( 9, -9)[/tex]
Substituting according to the data we have:
[tex]- \frac {4} {3} = \frac {-9-y} {9-3}\\- \frac {4} {3} = \frac {-9-y} {6}\\6 * - \frac {4} {3} = - 9-y\\-8 = -9-y\\y = -9 + 8\\y = -1[/tex]
Answer:
[tex]y = -1[/tex]
