Well if you're wanting to use substitution, you first have to end up with one term on either side of the equation. Use the second one as it's easiest.
So: x-2y=11, so find -2y as there is a -2y in the first equation.
then that becomes -2y=11-x. then sub that into equation 1, and you get:
-x+11-x=-13, which equals to -2x+11=-13, which is -2x=-24, so therefore
x=12. then chuck the x into any of the equations to find what y equals.
hope this helps!
Answer:
The required sample size for the new study is 801.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
The margin of error is:

25% of all adults had used the Internet for such a purpose
This means that 
95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
What is the required sample size for the new study?
This is n for which M = 0.03. So






Rounding up:
The required sample size for the new study is 801.
Answer:
percent 88%
fraction 44/50
ratio 44:50
Step-by-step explanation:
Minimum value of the function is - 2
hope that helps