No.051 Find the Inverse Proportion Equation

POINT

For inverse proportion, y = a/x. First find a = xy from the given pair. Substitute into the equation to find the missing x or y.

Example

y is inversely proportional to x, and y = 6 when x = 2. Answer the following questions.

Express y in terms of x.

Find y when x = −3.

Find x when y = −8.

① y = 12/x ② y = −4 ③ x = −3/2

Practice

y = a/x · a = xy

y is inversely proportional to x, and y = 8 when x = 2. Answer the following questions.

Express y in terms of x.

Find y when x = −4.

Find x when y = 2.

\((1) y = 16/x (2) y = -4 (3) x = 8\)

y is inversely proportional to x, and y = 5 when x = −3. Answer the following questions.

Express y in terms of x.

Find y when x = 5.

Find x when y = −5.

\((1) y = -15/x (2) y = -3 (3) x = 3\)

y is inversely proportional to x, and y = −3 when x = 4. Answer the following questions.

Express y in terms of x.

Find y when x = −2.

Find x when y = 2.

\((1) y = -12/x (2) y = 6 (3) x = -6\)

y is inversely proportional to x, and y = −6 when x = −2. Answer the following questions.

Express y in terms of x.

Find y when x = 3.

Find x when y = −4.

\((1) y = 12/x (2) y = 4 (3) x = -3\)

y is inversely proportional to x, and y = 2 when x = 5. Answer the following questions.

Express y in terms of x.

Find y when x = −5.

Find x when y = −1.

\((1) y = 10/x (2) y = -2 (3) x = -10\)