3x-6+10x+15=35
10x+3x=35-15+6
13x=26
x=2
Answer: 
Step-by-step explanation:
The confidence interval for population mean is given by :-

Given : Sample size : n= 35 , large sample (n>30)
Mean difference : 
Standard deviation : 
Significance level : 
Critical value : 
Now, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students will be :-

Hence, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students = 
Answer:
-6
Step-by-step explanation:
Take a couple of differences and see:
11 -17 = -6
5 -11 = -6
The common difference is -6.
Answer:
x = 24
Step-by-step explanation:
1.) put the equations together and equal them to 180
2x + 4 + 6x - 16 = 180
2.) combine like terms
8x - 12 = 180
3.) divide both sides by 8
8x = 192
4.) simplify
x = 24
Honestly I don't know congruent so congrats I can't answer sorry