Need help ASAP pls thx

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

If f(x) = x+8 and g(x) = 4x- 3, find (f+g)(x)

Atextile fiber manufacturer is investigating a new drapery yarn, which the company claims has a mean thread elongation of 12 kilograms with a standard deviation of 0.5 kilograms. the company wishes to test the hypothesis upper h subscript 0 baseline colon mu equals 12 against upper h subscript 1 baseline colon mu less-than 12 using a random sample of n equals 4 specimens. calculate the p-value if the observed statistic is x overbar equals 11.8. round your final answer to five decimal places (e. g. 98.76543).