Answer:
The perimeter of rectangle is 
Step-by-step explanation:
Let
x-----> the length of the rectangle
y----> the width of the rectangle
we know that
----> equation A
---> equation B (area of the constructed figure)
substitute the equation A in equation B

using a graphing tool -----> solve the quadratic equation
see the attached figure
The solution is

Find the value of x
----> 
Find the perimeter of rectangle

Answer:
So the total is 400 and then you have 4 servings
so 400/4 = 100 cal per serving
We know that she spent $39, and has 3/4 of the original amount left. Our goal is to find the original amount. We can use the equation. x - 39 = 3/4x. Once we subtract x on the left hand side, we get -39 = -1/4x. Once we multiply -39 by -4, we get 146. She originally had $156.