The answer is 20n + 10 = 90 because the bar seats 10 people so you take 90-10 and you're left with 80. Four seats are at a table so you take 80/4 and you're left with 20. All you need to do now is reverse the order to fit the answer, and since you originally subtracted, you'd add. You could also do 20x4 + 10 and see that it equals 90 to check your answer.
All three are parts to the triangle congruence theorem. (ASA: angle side angle, AAS: angle angle side, SSA: side side angle). Is there an option D.?
substitute 
in the equation:
The graphs are curved, not segments ending in a point.
http://www.wolframalpha.com/input/?i=plot+y+%3D+sin+x+for+-3.2+%3C+x+%3C+3.2+and+-1.1+%3C+y+%3C+1.2
1, 3/3, 420/420 why such a wierd qustion
