Domain = {-3, 2}
Range = All real numbers
We can represent the range in interval notation as which is basically saying
. The range is all real numbers due to the arrows meaning the graph extends up and down forever. So any y value is possible.
Notice with the domain we only have 2 valid x values -3 and 2. No other x values are allowed. Normally we use an interval of some kind to set up the domain, but we only have a set of values instead. The curly braces indicate "set".
Let be the cost, respectively, of a notebook and a pen. If you buy 2 notebooks and 3 pens (which we know is a cost of $14.50), you spend
Similarly, if you buy 1 notebook and 2 pens (which we know is a cost of $7.50), you spend
These two equations form the following system:
Multiply the second equation by 2:
Subtract the first equation from the second:
So, a pen costs 0.5 dollars. Plug this equation in the second equation: