Variable y varies directly with variable x, and y = 4 when x = 7.

What is the value of x when y = 12?
Is it 21? Im not Sure

Question

Variable y varies directly with variable x, and y = 4 when x = 7.  

 

What is the value of x when y = 12?
Is it 21? Im not Sure

anonymous · Answer

y = kx

Plug in what we know:

4 = 7k

Divide 7 to both sides:

k = 4/7

So this is the constant, plug in what we know:

y = kx

It says when 'y = 12'

12 = 4/7x

Divide 4/7 to both sides or multiply by its reciprocal, 7/4.

7/4 * 12 = 21

x = 21

Yes, 21 is correct!

anonymous · Answer

@r_josh10

r_josh10 · Answer

Thank you Again You are the most helpful

r_josh10 · Answer

@iGreen