I'll help you on the first one. Anya test scores are 78 and 91. She has one more test and want to average between an 80-89 inclusive. Lets set up a inequality and call the remaining test x. 80<=(78+91+x)/3<=89 Multiply everything by 3 240<=169+x<=267 Subtract 169 from everything 71<=x<=98 In interval notation that would be [71,98] In set notation that would be{x|71<=x<=98} For the graph, I don't really understand. I think you just graph 71<=x<=98.
We can use the vertex form of a quadratic, , to find that . Plugging ordered pairs into g(x), we see that a = 1. For example, for , . Solving for a gives 1.
, to find that 
. Plugging 
ordered pairs into g(x), we see that a = 1. For example, for 
, 
. Solving for a gives 1.