A1 Unit 7 Test Practice (Variations)

Front

What is direct variation?

Back

Direct variation is a relationship between two variables where one variable is a constant multiple of the other. It can be expressed as y = kx, where k is the constant of variation.

Front

What is inverse variation?

Back

Inverse variation is a relationship between two variables where the product of the two variables is a constant. It can be expressed as xy = k, where k is the constant.

Front

If y varies directly as x and y = 10 when x = 5, what is the constant of variation?

Back

The constant of variation k = y/x = 10/5 = 2.

Front

If y varies inversely as x and y = 20 when x = 4, what is the constant of variation?

Back

The constant of variation k = xy = 20 * 4 = 80.

Front

How do you find the value of y when y varies directly as x?

Back

To find y, use the formula y = kx, where k is the constant of variation.

Front

How do you find the value of y when y varies inversely as x?

Back

To find y, use the formula y = k/x, where k is the constant of variation.

Front

What is the constant of variation in the equation y = 3x?

Back

The constant of variation is 3.

Front

What does the equation xy = 25 represent?

Back

The equation represents inverse variation.

Front

Is the table showing a direct variation if the values are (1, 2), (2, 4), (3, 6)? What is the constant of variation?

Back

Yes, the constant of variation is 2.

Front

If y = 15 when x = 3, what is y when x = 9 if y varies directly as x?

Back

y = 45.