Answer:
[tex]y=\frac{63}{x}[/tex]
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
[tex]y=\frac{k}{x}[/tex]
where k is the constant of proportionality
y=7, x=9 plug in the values and find out k
[tex]7=\frac{k}{9}[/tex]
Multiply 9 on both sides
63=k
an equation connecting y and x is [tex]y=\frac{k}{x}[/tex]
[tex]y=\frac{63}{x}[/tex]
b) work out the value of y when x=21
[tex]y=\frac{63}{x}[/tex]
Plug in 21 for x
[tex]y=\frac{63}{21}[/tex]
y=3
