Answer:
10 - 3n = 31
n = -7
Step-by-step explanation:
10 - 3n = 31
-3n = 31 - 10
-3n = 21
n = 21/-3
 
        
             
        
        
        
Answer:
Step 4 is where she made the error. 
Step-by-step explanation:
This step is actually known as the commutative property. That property states that we can change the order of numbers as long as we keep the signs and it maintains it's validity. 
 
        
             
        
        
        
I think that the best answer here would be that A = 40 degrees. 
        
             
        
        
        
Answer:

Step-by-step explanation:
We want to find the Riemann sum for  with n = 6, using left endpoints.
 with n = 6, using left endpoints.
The Left Riemann Sum uses the left endpoints of a sub-interval:

where  .
.
Step 1: Find 
We have that 
Therefore, 
Step 2: Divide the interval ![\left[0,\frac{3 \pi}{4}\right]](https://tex.z-dn.net/?f=%5Cleft%5B0%2C%5Cfrac%7B3%20%5Cpi%7D%7B4%7D%5Cright%5D) into n = 6 sub-intervals of length
 into n = 6 sub-intervals of length 
![a=\left[0, \frac{\pi}{8}\right], \left[\frac{\pi}{8}, \frac{\pi}{4}\right], \left[\frac{\pi}{4}, \frac{3 \pi}{8}\right], \left[\frac{3 \pi}{8}, \frac{\pi}{2}\right], \left[\frac{\pi}{2}, \frac{5 \pi}{8}\right], \left[\frac{5 \pi}{8}, \frac{3 \pi}{4}\right]=b](https://tex.z-dn.net/?f=a%3D%5Cleft%5B0%2C%20%5Cfrac%7B%5Cpi%7D%7B8%7D%5Cright%5D%2C%20%5Cleft%5B%5Cfrac%7B%5Cpi%7D%7B8%7D%2C%20%5Cfrac%7B%5Cpi%7D%7B4%7D%5Cright%5D%2C%20%5Cleft%5B%5Cfrac%7B%5Cpi%7D%7B4%7D%2C%20%5Cfrac%7B3%20%5Cpi%7D%7B8%7D%5Cright%5D%2C%20%5Cleft%5B%5Cfrac%7B3%20%5Cpi%7D%7B8%7D%2C%20%5Cfrac%7B%5Cpi%7D%7B2%7D%5Cright%5D%2C%20%5Cleft%5B%5Cfrac%7B%5Cpi%7D%7B2%7D%2C%20%5Cfrac%7B5%20%5Cpi%7D%7B8%7D%5Cright%5D%2C%20%5Cleft%5B%5Cfrac%7B5%20%5Cpi%7D%7B8%7D%2C%20%5Cfrac%7B3%20%5Cpi%7D%7B4%7D%5Cright%5D%3Db)
Step 3: Evaluate the function at the left endpoints






Step 4: Apply the Left Riemann Sum formula

