The quadrilateral have equal opposite sides, for example:
Then, (4x + 6) must be equal to (7x - 3), and (4y - 3) is equal to (3y + 1), therefore

We can solve that equation for x

Hence, x = 3. Now let's solve the other equation

Then the value of y is 4.
Final answers:
x = 3
y = 4
Answer:
The answer to your question is $9.5
Step-by-step explanation:
Data
Large pizza = L
Medium pizza = m
Write equation for both situations
Situation 1 5L + 2m = 81.5
Situation 2 4L + 3m = 78.5
Solve the system of equation by elimination
Multiply situation 1 by -3 and situation 2 by 2
-15L - 6m = -244.5
8L + 6m = 157
-7L = -87.5
Solve for L L = -87.5/-7
L = $12.5
Substitute L in Situation 1 to find m
5(12.5) + 2m = 81.5
62.5 + 2m = 81.5
2m = 81.5 - 62.5
2m = 19
m = 19/2
m = $ 9.5
The prize of a medium pizza is $9.5