Answer:
x = 4 ±
Step-by-step explanation:
Given
(x - 12)(x + 4) = 9 ← expand the left side using FOIL
x² - 8x - 48 = 9 ( ad 48 to both sides )
x² - 8x = 57
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(- 4)x + 16 = 57 + 16
(x - 4)² = 73 ( take the square root of both sides )
x - 4 = ± ( add 4 to both sides )
x = 4 ±
Answer:
Step-by-step explanation:
-Let x be the sample size and n the population size
-The conditions for a one-sample proportion z-test are:
-The sample is randomly selected from the population.
-The sample size is greater than or equal to ten times the population size:
-The expectation np is greater than or equal to 10:
Answer: z= -1.636
Step-by-step explanation:
When population standard deviation is known, then the test statistic is given by :-
, where = sample mean,
= population mean, n=sample size ,
= standard deviation
As per given,
Hence, the e test statistic to see whether the candy bars are smaller than they are supposed to be : z= -1.636