Suppose y varies directly with x. Write a direct variation equation that relates x and y. Then find the value of y when x=18

Question

y= 7 when x= 6
Write a direct variation equation that relates x and y.

Answer 1

Since y varies directly with x, we can write the equation as:

y = kx

To find the value of k, we can use the given information that y = 7 when x = 6. Plugging these values into the equation:

7 = k * 6

To solve for k, we divide both sides of the equation by 6:

k = 7/6

So the direct variation equation that relates x and y is:

y = (7/6)x

To find the value of y when x = 18, we plug in x = 18 into the equation:

y = (7/6)(18) = 21