Question

1. y and x have a proportional relationship, and y = 7 when x = 2. What is the value of x when y = 21?

2. y and x have a proportional relationship, and y = 9 when x = 2. What is the value of y when x = 3?


3.he table shows a proportional relationship.




x y

2 2.8

4 5.6

6 8.4

8 11.2

Complete the equation that represents the table.


Enter your answer as a decimal in the box. y = ____x

Answer 1

I really hope this helps. Lol. I got it wrong but that doesn't mean you have to.

Explanation:

Answer 2

Proportional relationship states that one in which two quantities vary directly with each other.

In other words, we say the variable y varies directly as x if:

`y = kx` , where k is constant of proportionality.

(1)

Given: y and x varies a proportional relationship, and y = 7 and x=2

find the value of x when y =21

By the definition of proportional relationship;

y = kx ......[1]

Substitute the value y= 7 and x = 2 to solve for k;

`7 = 2k`

Divide by 2 to both sides we get;

`(7)/(2) =(2k)/(2)`

Simplify:

k = 3.5

Now, substitute the value of k = 3.5 and y =21 in equation [1] to find the value of x.

`21 = 3.5 x`

Divide both sides by 3.5 we get;

`(21)/(3.5) =(3.5x)/(3.5)`

Simplify:

x = 6

Therefore, the value of x is 6.

(2)

Given: y and x varies a proportional relationship, and y = 9 and x=2

find the value of y when x=3.

By the definition of proportional relationship;

y = kx ......[1]

Substitute the value y= 9 and x = 2 to solve for k;

`9 = k\cdot 2`

Divide by 2 to both sides we get;

`(9)/(2) =(2k)/(2)`

Simplify:

k = 4.5

Now, substitute the value of k = 4.5 and x=3 in equation [1] to find the value of y.

`y= 4.5 \cdot 3`

Simplify:

x = 13.5

Therefore, the value of y is 13.5.

(3)

From the given table,

y = 2.8 when x = 2

by the definition of proportional relationship;

`2.8 = k \cdot 2`

or

`2.8 =2k`

Divide by 2 to both sides, we get;

`(2.8)/(2) =(2k)/(2)`

Simplify:

k = 1.4

Therefore, the equation that represents the table is; y = 1.4 x