Answer: 
Step-by-step explanation:
We know that the standard quadratic equation is ax^2+bx+c=0
Let's compare all the given equation to it and , find discriminant.
1. a=2, b= -7, c=-9
So it has 2 real number solutions.
2. a=1, b=-4, c=4

So it has only 1 real number solution.
3. a=4, b=-3, c=-1

So it has 2 real number solutions.
4. a=1, b=-2, c=-8
So it has 2 real number solutions.
5. a=3, b=5, c=3

Thus it does not has real solutions.
Answer:
szdg
Step-by-step explanation:
hesre
Answer:
N = 9
M = 87.11
Step-by-step explanation:
According to the situation, the data provided and the solution are as follows
The scores for the student in the classroom is
= 88 88 92 88 88 72 96 88 84
The different student's number of scores is 9
The solution of new n and M is shown below:-
Sample size (n) = 9
Sample mean (m) is

= 

= 87.11
Answer:
give the full questions please