GMAT Math : Algebra

Study concepts, example questions & explanations for GMAT Math

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Example Questions

Example Question #3 : Absolute Value

Solve for  in the absolute value equation

 

Possible Answers:

None of the other answers

Correct answer:

None of the other answers

Explanation:

The correct answer is that there is no .

 

We start by adding  to both sides giving

 

 

Then multiply both sides by .

 

 

Then divide both sides by 

 

 

Now it is impossible to go any further. The absolute value of any quantity is always positive (or sometimes ). Here we have the absolute value of something equaling a negative number. That's never possible, hence there is no  that makes this a true equation.

Example Question #4 : Absolute Value

Solve the following equation:

 

Possible Answers:

Correct answer:

Explanation:

We start by isolating the expression with the absolute value:

  becomes 

So:  or 

We then solve the two equations above, which gives us 42 and 4 respectively.

So the solution is 

Example Question #2 : Understanding Absolute Value

Solve the absolute value equation for .

 

Possible Answers:

The equation has no solution

None of the other answers.

Correct answer:

Explanation:

We proceed as follows

 

(Start)

(Subtract 3 from both sides)

or (Quantity inside the absolute value can be positive or negative)

 

or  (add five to both sides)

or

 

Another way to say this is

Example Question #3 : Absolute Value

Which of the following could be a value of ?

 

Possible Answers:

Correct answer:

Explanation:

To solve an inequality we need to remember what the absolute value sign says about our expression. In this case it says that

     

can be written as

 Of .

Rewriting this in one inequality we get:

From here we add one half to both sides .

Finally, we divide by two to isolate and solve for m.

Only  is between -1.75 and 2.25

Example Question #11 : Understanding Absolute Value

The absolute value of negative seventeen is multiplied by a number that is three fewer than twelve. The resulting number is subtracted from negative six. What number is yielded at the end of this sequence of operations?

Possible Answers:

Correct answer:

Explanation:

This is a problem where we need to use our translating skills. We are given a word problem and asked to solve it. To do so, we need to rewrite our word problem as an equation and then use arithmetic to find the answer. In these types of problems, the hardest step is usually translating correctly, so make sure to be meticulous and work step-by-step!

1)"The absolute value of negative seventeen": Recall that absolute value means that we will just change the sign to positive. Missing that will end up giving you the trap answer .

2)"is multiplied by a number which is three fewer than twelve." We need a number that is three fewer than twelve, so we need to subtract. Follow it up with multiplication and you get:

3)"The resulting number is subtracted from negative six." The key word here is "from"—make sure you aren't computing , which would result in another one of the trap answers!

The correct answer is .

Example Question #11 : Understanding Absolute Value

Solve .

Possible Answers:

  or 

 

 

  or 

Correct answer:

  or 

Explanation:

Since we are solving an absolute value equation, , we must solve for both potential values of the equation:

1.) 

2.) 

Solving Equation 1:

Solving Equation 2:

Therefore, for  or .

Example Question #12 : Understanding Absolute Value

Solve .

Possible Answers:

 or 

 or 

Correct answer:

 or 

Explanation:

Since we are solving an absolute value equation, , we must solve for both potential values of the equation:

1.) 

2.) 

Solving Equation 1:

Solving Equation 2:

Therefore, for  or .

Example Question #11 : Understanding Absolute Value

Define an operation  as follows:

For all real numbers ,

Evaluate: 

Possible Answers:

Correct answer:

Explanation:

Example Question #12 : Understanding Absolute Value

Define an operation  as follows:

For all real numbers ,

Evaluate 

Possible Answers:

Correct answer:

Explanation:

Example Question #445 : Algebra

Define an operation  as follows:

For all real numbers ,

Evaluate 

Possible Answers:

Correct answer:

Explanation:

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