Answer:
6x + 12y = 816
Step-by-step explanation:
6 dollars per regular admission
12 dollars per both dance and volleyball
in total 816 dollars
1) Expand by distributing terms
7a+7 x-3
Simplify 7x-3 to -21
7a-21
200 can be rounded down to 200, which is easy to add with. Thus, an estimate is 222+200=422.
Alternatively, you could round 222 up a bit, to get 225+200=425. This is actually the correct answer, but this rounding doesn't make the calculation easier, so if you needed a quick estimate I'd go with the first option.