Answer:
B
Step-by-step explanation:
17.3&
The two equations are

and

the first equation can be solved for x to be

next you can substitute x in the second equation

Distribute 4 to everything in the parentheses

combine like terms:

subtract 28 from both sides of the equation

divide both sides by -1.5

plug this in to the original equation of x+y=7

subtract 4 from both sides.

Final Answer: they bought 3 adult tickets and 4 student tickets
Hope this helps!
The property applied is the associative property
<h3>Algebraic properties</h3>
There are several algebraic properties in mathematics; each of which have their own applications
Some of these properties are:
- Commutative
- Distributive
- Associative
- Identity
The mathematical expression is given as:

And it is calculated as follows:


The property applied above is the associative property
Read more about mathematical properties at:
brainly.com/question/10628093