A problem like this one is very easy.  All you need to do is manage your arithmetic well.  Remember that when you subtract a negative number, this is the same as adding the positive of that number.  Therefore, you can rewrite each of your quantities:

Quantity A: 

Using a calculator, this comes out to be: 

Quantity B:

Using a calculator, this comes out to be: 

Therefore, quantity B is larger.

The answer is 

Make sure to distribute negatives throughout the second half of the equation.

To solve this problem, you need to get your variable isolated on one side of the equation:

Taking this step will elminate the  on the side with :

Now divide by  to solve for :

The important step here is to be able to add the negative numbers.  When you add negative numbers, they create lower negative numbers (if you prefer to think about it another way, you can think of adding negative numbers as subtracting one of the negative numbers from the other).  

To solve this problem, first you must add  to both sides of the problem.  This will yield a result on the right side of the equation of , because a negative number added to a negative number will create a lower number (i.e. further away from zero, and still negative).  Then you divide both sides by two, and you are left with .

To solve for , divide each side of the equation by -2.

  is the same as

  which is POSITIVE  

A negative number divided by a negative number always results in a positive number.  divided by  equals . Since the answer is positive, the answer cannot be  or any other negative number.

Begin by isolating your variable.

Subtract  from both sides:

, or 

Next, subtract  from both sides:

, or 

Then, divide both sides by :

Recall that division of a negative by a negative gives you a positive, therefore:

 or 

To solve this equation, you need to isolate the variable on one side. We can accomplish this by dividing by  on both sides:

Anytime you divide, if the signs are the same (i.e. two positive, or two negative), you'll get a positive result.  If the signs are opposites (i.e. one positive, one negative) then you get a negative.  

Both of the numbers here are negative, so we will have a positive result:

To solve, you need to isolate the variable. We first subtract  then divide by :

When dividing, if the signs of the numbers are the same (i.e. both positive, or both negative), you yield a positive result.  If the signs of the numbers are opposites (i.e. one of each), then you yield a negative result.  

Therefore:

Recognize the rules of negative numbers: if two negative numbers are multiplied, the result is positive. However if three negative numbers are multiplied, the result is negative. As such, we know B must be negative.

Since there are no restrictions on the values of x, y and z beyond being negative, lets check low values and high values: if every value was -1, multiplying the values would equal -1 while adding them would equal -3. However, if every value was -5, multiplying them would equal -125 while adding them would equal a mere -15. As such, we would need additional information to determine whether A or B would be greater.