Answer:
A) C) E)
Step-by-step explanation:
ON edge
H²+10h+21 = 0
h²+3h+7h+21 = 0
h(h+3)+7(h+3) = 0
(h+3)(h+7) = 0
h+3=0
h = -3
h+7=0
h=-7
Answer: c. z = 1.35; Reject the null hypothesis
Step-by-step explanation:
Let
be the average life expectancy of its batteries.
As per given , we have
Null hypothesis : 
Alternative hypothesis : 
Since
is right-tailed and population standard deviation is also known, so we perform right-tailed z-test.
Test statistic : 
where, n= sample size
= sample mean
= Population mean
=population standard deviation
For
, we have

Critical one-tailed test value for 0.10 significance level :

Decision : Since critical z value (1.28) < test statistic (1.35), so we reject the null hypothesis .
[When critical value is less than the test statistic value , we reject the null hypothesis .]
Answer:
The bottom one: The value is the difference of 42 and the sum of 20 and 3.
Step-by-step explanation:
The answer is what you get when you subtract 23 from 42. Using "the difference" means subtraction is involved and you expression is 42 - (minus) (20+3).
Answer: 
Step-by-step explanation:
You have the equation
.
Then, to solve for the variable
from the equation you need:
Make the subtraction of the right side of the equation:
(As the denominators are 1 and
, the least common denominator is
)

Multiply
to both sides:

Add
to both sides:

And finally divide both sides by
:
