Question

30 POINTSSSSSS If y varies directly as x, and y = 42 as x = 6, find y for the x-value 3

Answer 1

`\\ \sf\longmapsto x\propto y`

`\\ \sf\longmapsto x_1y_2=x_2y_1`

`\\ \sf\longmapsto 6y_2=42(3)`

`\\ \sf\longmapsto 6y_2=126`

`\\ \sf\longmapsto y_2=(126)/(6)`

`\\ \sf\longmapsto y_2=21`

Answer 2

• y = 7x
• y = 21

Explanation:

Direct variation formula:

• y = kx

Given:

• x = 6, y = 42

Find k:

• 42 = 6k
• k = 42/6
• k = 7

The equation of line is:

• y = 7x

Now, when x = 3, the value of y is:

• y = 7*3 = 21