Suppose y varies directly with x. Write a direct variation equation that relates x and y. Then find the value of y when x = 15.
y=9 when x =5
Write a direct variation equation that relates x and y. (Simplify your answer.)
y=
kx (where k is the constant of variation)
To find the value of k, we can substitute the given values of x and y into the equation and solve for k:
9 = k(5)
Divide both sides by 5:
k = 9/5
Now that we have the value of k, we can write the direct variation equation as:
y = (9/5)x
To find the value of y when x = 15, substitute x = 15 into the equation:
y = (9/5)(15)
y = 135/5
y = 27