Answer:
A
Step-by-step explanation:
there is a common ratio between consecutive terms , that is
- 12 ÷ - 3 = - 48 ÷ - 12 = - 192 ÷ - 48 = 4
this indicates the sequence is geometric with nth term
= a₁ 
where a₁ is the first term and r the common ratio
here a₁ = - 3 and r = 4 , then
a₈ = - 3 ×
= - 3 × 16,384 = - 49,152
By using dimensional analysis, this problem can be simple.

B
Answer:
a) P(X≥143)=0
b) This contradicts the study as getting a sample with this proportion is almost impossible (if the proportion of 68% is true).
Step-by-step explanation:
If we use the normal approximation to the binomial distribution we have the following parameters (mean and standard deviation):

Then, we can calculate the probability of X being equal or more than 143 using the z-score:

This contradicts the study as getting a sample with this proportion is almost impossible (if the proportion of 68% is true).
Answer:
B. (x+2) is a factor
Step-by-step explanation:
3x^2 -x-14
3x^2+6x-7x-14
3x(x+2)-7(x+2)
(3x-7)(x+2)
so, x+2 is a factor of 3x^2-x-14