Question

Y is inversely proportional to x

when y=7, x=9
a) work out an equation connecting y and x
b) work out the value of y when x=21

Answer 1

The equation that connects y and x is y = 63/x. When x = 21, the value of y is 3.

Step-by-step explanation:

When we say that y is inversely proportional to x, we mean that y = k/x, where k is the constant of proportionality. To find this constant, we use the given values: when y = 7, x = 9. Therefore, 7 = k/9, so the constant k is 63 (because 7 * 9 = 63). This gives us our equation: y = 63/x.

Now, we need to work out the value of y when x = 21. Plugging 21 into our equation gives y = 63/21. Simplify this and you get y = 3.

Answer 2

`y=(63)/(x)`

y=3

Step-by-step explanation:

y is inversely proportional to x

when y=7, x=9

When y is inversely proportional to x , then the equation is

`y=(k)/(x)`

where k is the constant of proportionality

y=7, x=9 plug in the values and find out k

`7=(k)/(9)`

Multiply 9 on both sides

63=k

an equation connecting y and x is
`y=(k)/(x)`

`y=(63)/(x)`

b) work out the value of y when x=21

`y=(63)/(x)`

Plug in 21 for x

`y=(63)/(21)`

y=3