Exercise 7 Page 526

We are told that

x

and

y

vary inversely. Knowing this, we want to write a function that models this inverse variation. Let's recall the general function form for inverse variation.

y = \frac{k}{x}

In this formula,

k

is the constant of variation and it cannot equal

0 .

To find its value we will substitute the given values,

x = 13

and

y = 17,

into the formula.

y = \frac{k}{x}

SubstituteII

$x = 13$ , $y = 17$

17 = \frac{k}{1 3}

MultEqn

$LHS \cdot 13 = RHS \cdot 13$

221 = k

RearrangeEqn

Rearrange equation

k = 221

Now that we know that

k = 221,

we can write the function form for the given inverse variation.

y = \frac{2 2 1}{x}