3x +3 + x = -1
4x= -4
X= -1
Answer:

Step-by-step explanation:
Factor
out of 
Answer: 7
Step-by-step explanation:
f(x) 3x+1
f(2) = 3(2) +1
f(2) = 6+1
= 7
Answer: 95.45 %
Step-by-step explanation:
Given : The distribution is bell shaped , then the distribution must be normal distribution.
Mean : 
Standard deviation :
The formula to calculate the z-score :-

For x = 13

For x = 19

The p-value = 

In percent, 
Hence, the percentage of data lie between 13 and 19 = 95.45 %