Beforehand let me apologize for my sloppy handwriting. I'm a lefty, so please deal with me. . Anyway, the equation you listed didn't really have a x, because a linear equation is y= mx+b, and anything with x is the slope. But I did see y and a number on one side, so I'm like maybe I can get these two alone. So here's what I did: 
2y + 4=0
 -4 -4 I subtracted 4 on both sides. Why because you would want "y" alone. 
Next, 
2y= -4 
Now to get "y" alone you want to divide on both sides. 
2y= -4/ 2
y= -2
Now you're probably thinking "how do you graph it? There's no "x" in the equation." Well, you just graph it. Since the answer is y= -2, you go to the y axis, look for -2, and place a line to indicate that is the equation. And to make it clear, remember y is the y-intercept. 
I really do hope this helps you, if not message me. I'll be happy to help, and again I'm sorry for my handwriting! 
 
        
        
        
Answer:
choice C. Yes, this image proves the pythagorean theorem is true because 9 + 16 = 25
Step-by-step explanation:
 
        
             
        
        
        
Answer: Step-by-step explanation:
57 - 10x = 45
-10x=-12
x=1.2
- 3y + 10x = -5
-3y+10=-5
-3y=-15
y=5
 
        
                    
             
        
        
        
Answer:
c) 2 + 3 = 5                   TRUE
d) 2 + (–3) = -1              True
Step-by-step explanation:
When adding integers (positive and negative whole numbers), there are three cases:
- Positive and positive increases and sum is positive. Ex. 4 + 6 = 10
- Positive and negative where you subtract and take the sign of the larger number. Ex. 3 + -8 = -5 or -3 + 8 = 5
- Negative and negative decrease and the sum if negative. Ex. -4 + -6 = -10.
Use these rules to simplify each expression.
a) 2 + (–3) = -1 not 1     FALSE
b) –3 + 2 = -1 not 5      FALSE
c) 2 + 3 = 5                   TRUE
d) 2 + (–3) = -1              True