ANSWER
A. y = 625 + 5x ___(1)
y = 449 + 6x ___(2)
B. $1505 and 176 diners
C. Each restaurant will donate $1505 with 176 diners promising to participate.
Step-by-step explanation
Let the amount that each restaurant contributes be y.
Let the number of diners promising to participate be x.
For the Italian restaurant, we have that they will make a donation of $625 and $5 per diner that night. This means that:
y = 625 + 5 * x
=> y = 625 + 5x ______(1)
For the Mexican restaurant, we have that they will contribute $449 plus $6 per diner. This means that:
y = 449 + 6 * x
y = 449 + 6x ______(2)
Now, we have a system of equations:
y = 625 + 5x ___(1)
y = 449 + 6x ___(2)
Using substitution method, we will substitute the second equation into the first one. That is:
449 + 6x = 625 + 5x
Collect like terms:
6x - 5x = 625 - 449
x = 176 diners
To find the value of y, substitute this value of x into equation (1):
=> y = 625 + 5(176)
y = 625 + 880
y = $1505
Therefore, each restaurant will donate $1505 with 176 diners promising to participate.