How to determine if a function y varies directly with x from a table

The video tutorial explains how to determine if Y varies directly with X using a table of values. Direct variation is defined as Y = KX, where K is a constant. To verify direct variation, calculate Y/X for each pair of coordinates. If the value of K is consistent across all pairs, Y varies directly with X. The tutorial demonstrates this with examples, showing that the constant K remains the same, confirming direct variation.

What is the formula for direct variation?

• Y = X + K

• Y = KX

• Y = K - X

• Y = K + X

How can you express direct variation using a ratio?

• Y - X = K

• Y / X = K

• Y * X = K

• X / Y = K

What must be true for a function to show direct variation in a table?

• The ratio Y/X must be constant.

• The product of Y and X must be constant.

• The difference between Y and X must be constant.

• The sum of Y and X must be constant.

In the example provided, what is the constant K for the points given?

• 7

• 5

• 8

• 6

If Y = 21 and X = 3, what is the value of K?

• 5

• 6

• 7

• 8