Interior angle add up to 360, so you add
(a+10) + (3a+10) + (5a-10) + (3a-10) = 12a
12a =360
a= 30
30+10=40
3(30)+10=100
5(30)-10=140
3(30)-10=80
You can double check they're correct by doing 40+100+140+80, which equals 360.
        
             
        
        
        
Answer:
=(a-b)(a^2+ab+b^2)
= a^3+a^2b+ab+ab^2-ba^2-ab^2-b^3
SIMPLIFY
=a^3+ab-b^3
 
        
             
        
        
        
Answer:
15 5/8 ft^3
Step-by-step explanation:
Volume of a cube = l x b x h
Given the Length of sides is 
2 1/2
Change 2 1/2 to an improper fraction.
It becomes 5/2
Volume = 5/2 x 5/2 x 5/2
Multiply through 
= 125/8
= 15 5/8 ft^3
 
        
             
        
        
        
Answer: 8 hours
Step-by-step explanation:
Let x be the time taken by each person to paint the fence.
Given: Tom and Becky can paint Jim's fence together in 12 hours. 
Since all people paint at the same rate, then we have the following equation ;-

Thus, the time taken by each person to paint the fence alone = 24 hours
Now, the time taken by all three paint together:-

Hence, it would take 8 hours if all three paint together.
 
        
             
        
        
        
All you have to do is addition. 2+5+4=11. Or you can break it down and go 2+5=7 and then 7+4=11. Or 5+4=9 then 9+2=11. Or 4+2=6 then 6+5=11.