12.
Add like terms from both trinomials:



Combine these terms to get a new trinomial as your answer:

13.
Subtract like terms from both trinomials (note that subtracting a negative is the same as adding it as a positive):



0 can be left out of the answer.
Combine these terms to get a binomial as your answer:
24 months. 1 year equals 12 months. 12x2=24
<h2><u>
Answer with explanation</u>
:</h2>
Let
be the average life of light bulbs.
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.
Formula for Test statistic : 
where, n= sample size
= sample mean
= Population mean
=population standard deviation
For
, we have

Using z-value table , Critical one-tailed test value for 0.06 significance level :

Decision : Since critical z value (1.5548) < test statistic (1.6180), so we reject the null hypothesis .
[We reject the null hypothesis when critical value is less than the test statistic value .]
Conclusion : We have enough evidence at 0.06 significance level to support the claim that the new filament yields a longer bulb life
The hour has stayed the same. 36-22 is 14. That's 14 minutes between.
Answer:
Step-by-step explanation:
Hence, the surface area of a triangular pyramid is 140 square units.