Answer:
f(x) = -4x + 12
Step-by-step explanation:
y - 2x = -6x + 12
+2x        +2x
f(x) = -4x + 12
 
        
             
        
        
        
Number of faces: F=a+3
Number of vertices: V=2a
Number of edges: E=4a-1
V+F-E=2
Replacing V=2a; F=a+3; and E=4a-1 in the formula above:
(2a)+(a+3)-(4a-1)=2
Eliminating parentheses:
2a+a+3-4a+1=2
Adding similar terms:
(2+1-4)a+(3+1)=2
(-1)a+4=2
Solving for a. Subtracting 4 both sides of the equation:
(-1)a+4-4=2-4
(-1)a=-2
Dividing both sides by (-1)
(-1)a/(-1)=-2/(-1)
a=2
Answer: The value of a is: a=2
        
                    
             
        
        
        
Answer:
3000 books.
Step-by-step explanation:
Let x be total number of books.
3% is 3/100.
So:
3x/100=90
3x=9000
x=3000 books
 
        
             
        
        
        
Answer:
Torrance spends 16$ on his brother
Step-by-step explanation:
You have 100$
So, we have
x (brother) + x (sister) + x (mother) = 100
But, since 10$ less will be spent on the sister than the brother, it becomes (x - 10) and twice + 6$ is spent on the mom, it also becomes (2x + 6)
Our equation then becomes
(x - 10) + x + (2x + 6) = 100
X will end up equaling 26. This is how much is spent on the sister.
(x - 10) will be substituted for (26 - 10), which equals 16.
I'm not sure if this is right so you might want to check with somebody (since I may be wrong) I hope this helps you understand how to basically do it though. <3