The value of x when y = 84 is 14
From the question,
The value of y varies directly with x
That is,
y ∝ x
Introducing the constant of proportionality, k
We get,
y = kx
Also, from the question
If x = 3, then y = 18
Putting these values into the equation, we can determine the value of k
[tex]y = kx[/tex]
[tex]18 = k \times 3[/tex]
Now, divide both sides by 3
[tex]\frac{18}{3}=\frac{k \times 3}{3}[/tex]
[tex]6 = k[/tex]
∴ k = 6
Now, to determine the value of x when y = 84
We will put y = 84 and the value of k =6 into the equation
[tex]y = kx[/tex]
[tex]84 = 6 x[/tex]
Divide both sides by 6
[tex]\frac{84}{6} = \frac{6x}{6}[/tex]
[tex]14 = x[/tex]
∴ [tex]x = 14[/tex]
Hence, the value of x when y = 84 is 14
Learn more here: https://brainly.com/question/17531464
