Looking at the question we can see that it says: 

We should know what these symbols mean: 
 stands for something less than the other, for example:
 stands for something less than the other, for example: 
We can say that 2 is less than 5 so in a symbolic form it can be written as, 
 
 
Similarly, 
 stands for something greater than the other, for example:
 stands for something greater than the other, for example: 
We can say that 7 is greater than 5, in a symbolic form it can be written as, 

So here,  means that, 42153 is greater than 35214.
 means that, 42153 is greater than 35214. 
 
        
                    
             
        
        
        
Let: x = number of copies sold
We can formulate the following equation to solve for x:
1.50x - 0.9x - 600 = 0
x = 1000
Therefore, the club must sell 1000 copies to break even. Among the choices, the correct answer is A. 
        
             
        
        
        
Its an indirect proof, so 3 steps :-
1) you start with the opposite of wat u need to prove 
2) arrive at a contradiction
3) concludeReport · 29/6/2015261
since you wanto prove 'diagonals of a parallelogram bisect each other', you start wid the opposite of above statement, like below :- step1 : Since we want to prove 'diagonals of a parallelogram bisect each other', lets start by assuming the opposite, that the diagonals of parallelogram dont bisect each other.Report · 29/6/2015261
Since, we assumed that the diagonals dont bisect each other, 
OC≠OA 
OD≠OBReport · 29/6/2015261
Since, OC≠OA, △OAD is not congruent to △OCBReport · 29/6/2015261
∠AOD≅∠BOC as they are vertical angles, 
∠OAD≅∠OCB they are alternate interior angles 
AD≅BC, by definition of parallelogram 
so, by AAS, △OAD is congruent to △OCBReport · 29/6/2015261
But, thats a contradiction as we have previously established that those triangles are congruentReport · 29/6/2015261
step3 :
since we arrived at a contradiction, our assumption is wrong. so, the opposite of our assumption must be correct. so diagonals of parallelogram bisect each other.
        
             
        
        
        
X=5 if that's what you were asking for
        
             
        
        
        
Answer:
- 
Step-by-step explanation:
Find slope using the slope formula : 
Plug in the given points : 
Add the numbers : 
Calculate the difference : 
Reduce the fraction : -
Solution : -