SOLUTION: "Tell whether this equation represents a direct variation. If so, identify the constant of variation." The value of y varies directly with x, and y = 2 when x = -3. Find y when

Algebra ->  Coordinate-system -> SOLUTION: "Tell whether this equation represents a direct variation. If so, identify the constant of variation." The value of y varies directly with x, and y = 2 when x = -3. Find y when      Log On


   

Question 934505: "Tell whether this equation represents a direct variation. If so, identify the constant of variation."
The value of y varies directly with x, and y = 2 when x = -3. Find y when x = 6.
1) I don't know what is implied/what info I can glean from the fact that y varies directly with x.
2) I don't know how to determine the equation/relationship between x and y with one data point.
I'm sorry I can't show any work, but I don't understand what to do with the information given in the problem. Any help you can give about this topic in general and about the specific problem would be appreciated. Thanks.
Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
direct variation is y = x (y varies directly) and inverse variation is y = 1/x (y varies inversely), therefore in this problem we have
y = k * x where k is the constant of proportionality
2 = k * -3
-3k = 2
k = -2/3
now we are asked to find y when x = 6
y = (-2/3) * 6
y = -4