Direct, Joint, Inverse and Combined Variation

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 a non-zero constant.

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 y = k/x, where k is a non-zero constant.

Front

What is joint variation?

Back

Joint variation is a relationship where a variable varies directly as the product of two or more other variables. It can be expressed as y = kxz, where k is a non-zero constant, and x and z are the other variables.

Front

What is combined variation?

Back

Combined variation is a relationship that involves both direct and inverse variation. It can be expressed as y = kx/z, where k is a non-zero constant.

Front

If f varies directly as g and inversely as h, how can you express this relationship mathematically?

Back

f = k(g/h), where k is a constant.

Front

If y varies directly as x and y = 39 when x = 3, what is the value of y when x = 2?

Back

y = 26.

Front

If y varies jointly as x and z, and y = -180 when z = 15 and x = -3, what is the value of y when x = 7 and z = -5?

Back

y = -140.

Front

If p varies directly as r and inversely as t, and t = 20 when p = 4 and r = 2, what is the value of t when r = 10 and p = -5?

Back

t = -80.

Front

What is the formula for direct variation?

Back

y = kx, where k is a non-zero constant.

Front

What is the formula for inverse variation?

Back

y = k/x, where k is a non-zero constant.