Answer:
a) System of equations will be:
![x+y=500\: and\:5x+2y=1789](https://img.qammunity.org/2021/formulas/mathematics/high-school/7jg28njzj98jkhzrey2wsih4wnnqbz77eg.png)
b) Number of adult tickets sold = 263
Number of students tickets sold = 237
Explanation:
Let:
Number of adult tickets sold = x
Number of students tickets sold = y
a)
As Marc sold total 500 tickets, the expression will be:
![x+y=500](https://img.qammunity.org/2021/formulas/mathematics/middle-school/xi8z9kn9ov9860p9rpk623s3zlzk0tjz9q.png)
Student tickets cost $2 and adult tickets cost $5. Marc's sales totalled $1,789.
The expression will be:
![5x+2y=1789](https://img.qammunity.org/2021/formulas/mathematics/high-school/10td6nmaml3fqveba5en0mzshwani1d01c.png)
So, system of equations will be:
![x+y=500\: and\:5x+2y=1789](https://img.qammunity.org/2021/formulas/mathematics/high-school/7jg28njzj98jkhzrey2wsih4wnnqbz77eg.png)
b)
Solve the system to find value of x and y
Let:
![x+y=500--eq(1)\\5x+2y=1789--eq(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/osavkljjvkr616m2oo4256k0agakl2z88z.png)
Multiply equation 1 by 2 and subtract
![2x+2y=1000\\5x+2y=1789\\-\:\:\:-\:\:\:\:\:\:\:\:\:-\\------\\-3x=-789\\x=(-789)/(-3)\\x=263](https://img.qammunity.org/2021/formulas/mathematics/high-school/w7poa0xaccxikbqc73abq1fwua56bqa16y.png)
We get value of x = 263
Now finding value of y by putting value of x in eq(1)
![x+y=500\\263+y=500\\y=500-263\\y=237](https://img.qammunity.org/2021/formulas/mathematics/high-school/nlwdxluzpcuybghyg32zwpxrdrrrn6k214.png)
We get value of y = 237
Number of adult tickets sold = x = 263
Number of students tickets sold = y = 237