Hello Again!
What you want to do first is add 4 to -4 and to -13. After doing so, you'll equation will look a little something like this...
-3x=9
You'll then want to divide both -3 and 9 by -3. After doing so, the equation will look like this...
x=-3
Your answer is x=-3
I hope this helps
Answer:
95% two-sided confidence interval on the true mean breaking strength is (94.8cm, 99.2cm)
Step-by-step explanation:
Our sample size is 11.
The first step to solve this problem is finding our degrees of freedom, that is, the sample size subtracted by 1. So
.
Then, we need to subtract one by the confidence level
and divide by 2. So:

Now, we need our answers from both steps above to find a value T in the t-distribution table. So, with 10 and 0.025 in the two-sided t-distribution table, we have 
Now, we find the standard deviation of the sample. This is the division of the standard deviation by the square root of the sample size. So

Now, we multiply T and s
cm
For the upper end of the interval, we add the sample mean and M. So the upper end of the interval here is
cm
So
95% two-sided confidence interval on the true mean breaking strength is (94.8cm, 99.2cm).
So this is going to be alot of writing to show my thinking but ill bold the answer.
1,1
1,2
1,3
1,4
1,5
2,1
2,2
2,3
2,4
2,5
3,1
3,2
3,3
3,4
3,5
4,1
4,2
4,3
4,4
4,5
5,1
5,2
5,3
5,4
5,5
next ill mark all the ones that equal 4 or 8 when added together, with an x
1,1
1,2
x1,3
1,4
1,5
2,1
x2,2
2,3
2,4
2,5
x3,1
3,2
3,3
3,4
x3,5
4,1
4,2
4,3
x4,4
4,5
5,1
5,2
x5,3
5,4
5,5
that is 6 (that equal 4 or 8) out of 25
so your ratio would be 6:19