I believe this should be right
 
        
        
        
Answer:
5 and -5
Step-by-step explanation:
3x² = 75
x² = 75/3
x² = √25
x = 5 and - 5
 
        
             
        
        
        
Write two equations with the given information:
1) x = 2y ( x is twice the value of y)
2) x + y = 42
Replace x in the second equation with the value of x in the first equation:
2y + y = 42
Simplify:
3y = 42
Divide both sides by 3:
y = 42 / 3
y = 14
Now we have the value for Y, solve for x by replacing y with 14:
x = 2y 
x = 2(14)
x = 28
X = 28 and y = 14
 
        
                    
             
        
        
        
6x
42/6 = 7 (valid), 18/6 = 3 (valid), 12/6 = 2 (valid)
7, 8, 9, 10, and 11 are all not divisible by 12, and 12 is not divisible by 18, so 6 is the highest number. 
Also, each number has at least one x, so you can take one out. 
Remaining=
6x (7 + 3x^2 + 2x^3)
        
             
        
        
        
Rewrite the equations;
m+4n=8
m-n=-2
Eliminating m gives;
5n=10
n=2
Replacing for n in the first equation;
m+4(2)=8
m=8
Answer;
(0, 2)