Question

1. Each pair of values below represents the values of two proportional variables. Give an equation for y in terms of x. (a) x=4 and y = 28 (b) x = 48 and y = 24 (C) x=14 and y=21

Answer 1

To write an equation in which y and x are proportional variables there must be an equation with a constant of proportionality like this:

`y=kx`

using the values of y and x find the value of the constant of proportionality.

a)

`\begin{gathered} 28=k\cdot4 \\ k=(28)/(4) \\ k=7 \end{gathered}`

the equation is

`y=7x`

b)

`\begin{gathered} 24=k\cdot48 \\ k=(24)/(48) \\ k=(1)/(2) \end{gathered}`

the equation is

`y=(1)/(2)x`

c)

`\begin{gathered} 21=k\cdot14 \\ k=(21)/(14) \\ k=(3)/(2) \end{gathered}`

the equation is

`y=(3)/(2)x`