The mean is not the same thing as median
mean=78+81+85+87=331
mean=331/4=82.75
median is the middle number, but you have a par set of numbers, so your median will be the middle numbers 78,81,85,87 , which are 81+85=166, 166/2=83
83 is your median
        
             
        
        
        
Answer:
1/5
Step-by-step explanation:
We can find the slope of a line given two points by using the following
m = ( y2-y1)/(x2-x1)
     = ( 3-0)/(7 - -8)
     = ( 3-0)/(7+8)
      = 3/15
     = 1/5
 
        
                    
             
        
        
        
Answer:
Step-by-step explanation:
U have to multiply 49 by 49 and then subtract 9
 
        
             
        
        
        
The general form of a quadratic (second degree) equation is 

, where

 is called the Discriminant.
The Discriminant determines how many roots the equation will have as follows:
i)  if D>0, the equation has 2 roots.
ii) if D=0, the equation has 1 double root.
iii) if D<0, the equation has no roots.
In our equation, 

, a=1, b=-5, c=7
so the discriminant is D=(-5)^2-4*1*7=25-28<0
Thus the equation has no roots.
Remark: the equation has no roots in the Real numbers, but it has 2 roots in a larger set of numbers to be discussed in the future, the Complex numbers.