Answer:

1. if y = 12, when x = 4, find y when x = 12

[tex]k = \frac{y}{x} [/tex]

[tex]k = \frac{12}{4} [/tex]

k = 3

find y when x = 12

y = kx

y = (3)(12)

y = 36

2. if y = -18, when x = 9, find y when x = 7

[tex]k = \frac{y}{x} [/tex]

[tex]k = \frac{ - 18}{9} [/tex]

k = -2

find y when x = 7

y = kx

y = (-2)(7)

y = 14