15x = 3x + 120 (subtract both sides by 3x)
12x = 120 (divide both sides by 12)
x = 100
        
                    
             
        
        
        
Answer:
A 
Step-by-step explanation:
Let's try choice A. 
y = -5x-4
(10, -52)
-52 = -5(10)-4
-52 = -50-4
-52= -54
-52 is not equal to -54, so A is the answer.
 
        
             
        
        
        
Answer: (-5x2 - 8x + 7) - (5x2 - 4)
Step-by-step explanation:
= -5x2 - 8x + 7 - 5x2 + 4
= -5x2 - 5x2 - 8x + 7 + 4
= -10x2 – 8x + 11
Answer: = (-5x2 - 8x + 7) - (5x2 - 4)
 
        
             
        
        
        
Answer:
Step-by-step explanation:
f(x) = x^2 + 5
g(x^2 + 5) = (x^2 + 5)^2= x^4 + 5x^2 + 5x^2 + 25 = x^4 + 10x^2 + 25
h(x^4 + 10x^2 + 25)= -2(x^4 + 10x^2 + 25)
                                   -2x^4 - 20x^2 - 50
 
        
             
        
        
        
The first option is correct (: