Complete the square
first isolate x terms
y=(x^2-4x)-9
complete square inside (take 1/2 of square of b )
-4/2=-2, (-2)^2=4
add 4-4 inside
y=(x^2-4x+4-4)-9
complete the square
y=((x-2)^2-4)-9
y=(x-2)^2-4-9
y=(x-2)^2-13
Answer:
x=9
Step-by-step explanation:
Similar triangles
8/20 = 6/(x+6)
==> 2/5 = 6/(x+6)
2/5x+12/5=6
2/5x=18/5
x=9
Answer: thats right...
Step-by-step explanation:
No, 50 is not a perfect square. A perfect square is any number that can be divided by any number to get the quotient as the same number AND the quotient must be rational. When you divide 50 so that the quotient equals the divisor, you will get an irrational number. Therefore, 50 is not a perfect square.
Answer:
The 95 percent confidence interval for the true mean metal thickness is between 0.2903 mm and 0.2907 mm
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, 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 lower end of the interval is the sample mean subtracted by M. So it is 0.2905 - 0.0002 = 0.2903 mm
The upper end of the interval is the sample mean added to M. So it is 0.2905 + 0.0002 = 0.2907 mm
The 95 percent confidence interval for the true mean metal thickness is between 0.2903 mm and 0.2907 mm