Answer:
Critical value: z = 1.28
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.
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 1-0.1 = 0.9, so z = 1.28
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.
So
The lower end of the interval is the mean subtracted by M. So 64.26 - 17.773 = $46.487.
The upper end of the interval is M added to the mean. So 64.26 + 17.773 = $82.033.
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.
Answer:
B
Step-by-step explanation:
in table B if x = 1 y cannot equal both 1 and -1
no function can have x equal to two or more unique y's
(4x + 7)² = 60
(4x + 7)(4x + 7) = 60
(4x² + 28x + 28x + 49) = 60
4x² + 56x + 49 = 60
<u> -49 -49</u>
4x² + 56x = 11
4x² + 56x - 11 = 11 - 11
4x² + 56x - 11 = 0
x = <u>-56 +/- √(56² - 4(4)(-11))</u>
2(4)
x = <u>-56 +/- √(3136 + 88)</u>
8
x = <u>-56 +/- √(3174)</u>
8
x = <u>-56 +/- 56.34</u>
8
x = -7 +/- 7.0425
x = -7 + 7.70425 x = -7 - 7.70425
x = 0.70425 x = -14.70425
Wait I’m confused can we at least see the picture
