So all the angles on one side should equal 180.
50+55= 105
180-105=75
12x+3=75
12x=72
12*6=72
x=6
        
             
        
        
        
Answer:
d. The population standard deviation is known.
Step-by-step explanation:
T-distribution or Z-distribution, which to use?
If we have the population standard deviation is known, we use the z-distribution.
Otherwise, if we only have the standard deviation for the sample, we use the t-distribution.
Which of the following is not appropriate to use the t-confidence interval for
When the population standard deviation is known, so letter d.
 
        
             
        
        
        
Answer:
(3, 0) and (5, 0)
Step-by-step explanation:
we have

we know that
The x-intercepts are the values of x when the value of y is equal to zero
so
For y=0

The formula to solve a quadratic equation of the form 
 
 
is equal to

in this problem we have
 
  
so

substitute in the formula





so
x=3, x=5
therefore
The x-intercepts are (3,0) and (5,0)
 
        
             
        
        
        
Can you buttress your point?