Question

Suppose y varies directly with x, and y = 12 when x = 2. What direct variation

equation relates x and y?
What is the value of y when x = 4?

Answer 1

`y=24`

Explanation:

Given:

`y=kx`

Substitute:

`\left \{ {{y=12} \atop {x=2}} \right.` into
`y=kx`

`12=k*2`

Swap the sides:

`k*2=12`

Divide both sides of the equation by the coefficient of variable:

`k=(12)/(2)`

Cross out the common factor:

`k=6`

Find the equation of the function:

`y=6x`

Substitute:

`y=6*4`

Calculate the product or quotient:

`y=24`