Answer:
n=21
Step-by-step explanation:
We must find n.
Remember PEMDAS. First we must do the Parentheses. Lets do distributive property by multiplying a number that is immediately outside the parentheses with each number inside the parentheses. Lets do this one side at a time.
First lets do 5(n - 7). We get 5n - 35
Now 2(n + 14) is 2n + 28
Okay...... now we have 
Now lets do OPPOSITES!!!! We must do the opposite of each thing to both sides.
The opposite of -35 is positive 35. Lets add 35 to both sides. We get:

Now lets do the opposite of 2n which is -2n

this is looking quite nice isnt it..........
The opposite of 3 times n is 3 DIVIDED BY n. So lets divide both sides by 3

amazing.......
1/2 x 3/4
1 x 3 / 2 x 4
= 3/8
Answer:
A. 8n-10
Step-by-step explanation:
8n2−26n+20/n−2
=2(4n−5)(n−2)/n−2
=8n−10
X²+y² =(Radius)²
x²+y² =10². So the radius is 10