Answer:
0
Step-by-step explanation:
Quadratic equation
The discriminant is the part of the quadratic formula within the square root symbol: 
. The discriminant indicates if there are two solutions, one solution, or none.
The discriminant can be positive, zero or negative which determines how roots exist for the given quadratic equation.
So, a positive discriminant tell us that the quadratic has two different real solutions.
A discriminant of zero tell us that the quadratic has two real and equal solutions.
And a negative discriminant tell us that none of the solutions are real numbers.
In this case: 25x^2-10x+1=0
We can see that
a= 25 b=-10 c=1
Using:
We have 
the answer is zero, so the quadratic has two real and equal solutions
<span>B. {-5,-4,-3…. }
............</span>
Answer:
We need a sample size of at least 75.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
So it is z with a pvalue of 
, so 
Now, we find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
The standard deviation is the square root of the variance. So:
With a .95 probability, the sample size that needs to be taken if the desired margin of error is 5 or less is
We need a sample size of at least n, in which n is found when M = 5. So
We need a sample size of at least 75.
