Determine whether y varies directly with x. If so, find the constant of variation k and write the equation.

X: 6, 18, 54, 162
Y: 24, 72, 216, 648

1 answer

To determine whether y varies directly with x, we can check if the ratio of y to x is constant. Let's calculate the ratio for each pair of corresponding values of x and y:

For x = 6, y = 24: y/x = 24/6 = 4
For x = 18, y = 72: y/x = 72/18 = 4
For x = 54, y = 216: y/x = 216/54 = 4
For x = 162, y = 648: y/x = 648/162 = 4

Since the ratio of y to x is constant and equal to 4, we can conclude that y varies directly with x.

The constant of variation, k, is equal to the ratio of y to x. In this case, k = 4.

The equation of variation is y = kx. Substituting k = 4, we get:

y = 4x