No, this is not a random group of students. Because Nina asked her friends if they liked the movie. For her to ask a random group of people, she would have to go and ask people that she did not know.
Answer:
Step-by-step explanation:
we have
-------> 
we know that
The formula to solve a quadratic equation of the form
is equal to
in this problem we have

so
substitute in the formula
Remember that

Answer:
Yes you are correct.
Step-by-step explanation:
The best way to check theese types of questions is go back in plug in X with your answer so 88+97+80+90(which is x)=360 then divide by 4 and get 90! So yes you are correct good job!