Question

the value of y varies directly with x, and y = 40 when x = 8.

what is y when x = 7?

y = ?

remember: y = kx

Explanation:

Set up the direct variation equation

Using the Linear Equations knowledge point, we start with the direct variation formula:

$$y = kx$$

where \(k\) is the constant of variation.

Solve for the constant of variation k

Using the One-Step Equations knowledge point, we substitute the given values \(y = 40\) and \(x = 8\) into the equation to find \(k\):

$$40 = k \cdot 8$$

$$k = \frac{40}{8} = 5$$

Calculate the value of y when x is 7

Now we use our determined constant \(k = 5\) and substitute \(x = 7\) back into the variation equation:

$$y = 5 \cdot 7$$

$$y = 35$$

Answer:

The value of y varies directly with x, and y = 40 when x = 8.

What is y when x = 7?

y = <blank>35</blank>