You have not provided the complete question (value of y at a certain value of x), therefore, I cannot give u a specific final answer. However, I can explain how to solve this problem and you can apply on the numbers you have.
y varies directly with x means that as x increases, y also increases and vice versa.
This can be represented by the following equation:
y = kx
where k is the constant of proportionality.
Solving this for k, we would find that:
k = y/x
Examples:
If we are given that y = 4 at x = 2, then:
k = y/x = 4/2 = 2
If we are given that y = 1 at x = 3, then:
k = y/x = 1/3
In general, if we are given that y = a at x = b, then:
k = a/b
Hope this helps :)
Answer:

Step-by-step explanation:
Given the slope and another point, simply plug them into the point-slope formula to find your y-intercept.

Now that we've found your y-intercept, we have the original equation. To find the perpendicular equation, you need the opposite reciprocal of your slope.
To find the 'opposite,' change your slope's sign. Since your slope is positive
, the opposite is
.
To find the 'reciprocal,' flip your fraction. This will make your slope
.
Your final equation is:

40÷5= 8 You have to see how many time 5 can go into 40
1. see how many times 5 goes into 4 none so the first number is 0
2. then you see how many time 5 can go into 0 o times
3. so you have to see how many time you can count 5 into 40
(count by 5's) 5,10,15,20,25,30,35,40 that should be 8 times total!
Since we are asked to find the rate of change from Monday to Wednesday, we are dividing by 2, since Monday is day 1 and Wednesday is day 3. 3 - 1 = 2.
1800 + 500 = 2300 calories consumed Tuesday.
2300 - 100 = 2200 calories Wednesday.
(2200 - 1800)/2 = 400/2 = 200 calories