I see this as a basic equation.
If she starts at point x, 8 feet, then goes down another 13, she is adding to the number of feet she traveled down.
So your answer would be 8+13=21
If this isn't what you needed, because I am not sure what math you are taking, let me know if I can help you more!
1-8 is simple. Just subtract 8 from 1. so 1-8 = -7
Answer:
-3
Step-by-step explanation:
Isolate -3y by subtracting x from both sides
-3y = -18 - x
Divide everything by -3
y = 6 + 1/3x
Slope is 1/3, and perpendicular lines have the reverse reciprocal slope, so our slope is -3
Answer:
For this case we want to test if do men give higher monetary donations than women in the month of December (alternative hypothesis) and the complement should be the null hypothesis. So then the sytem of hypothesis are:
Null hypothesis:
Alternative hypothesis : 
So then the best option would be:
d. Ha: mum -muw > 0
Step-by-step explanation:
Previous concepts
A hypothesis is defined as "a speculation or theory based on insufficient evidence that lends itself to further testing and experimentation. With further testing, a hypothesis can usually be proven true or false".
The null hypothesis is defined as "a hypothesis that says there is no statistical significance between the two variables in the hypothesis. It is the hypothesis that the researcher is trying to disprove".
The alternative hypothesis is "just the inverse, or opposite, of the null hypothesis. It is the hypothesis that researcher is trying to prove".
Solution to the problem
For this case we want to test if do men give higher monetary donations than women in the month of December (alternative hypothesis) and the complement should be the null hypothesis. So then the sytem of hypothesis are:
Null hypothesis:
Alternative hypothesis : 
So then the best option would be:
d. Ha: mum -muw > 0