GRE Subject Test: Math : Algebra

Study concepts, example questions & explanations for GRE Subject Test: Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #22 : Inequalities

\displaystyle 5\left | x-7\right |+14< 39

Possible Answers:

\displaystyle 2< x< 12

\displaystyle x< 12

\displaystyle 2< x

\displaystyle x> 12 or \displaystyle x< 2

Correct answer:

\displaystyle 2< x< 12

Explanation:

The first thing we must do is get the absolute value alone: \displaystyle 5\left | x-7\right |+14< 39

\displaystyle 5\left | x-7\right |< 25

\displaystyle \left | x-7\right |< 5

When we're working with absolute values, we are actually solving two equations:

\displaystyle x-7< 5     and \displaystyle x-7> -5

Fortunately, these can be written as one equation:

\displaystyle -5< x-7< 5

If you feel more comfortable solving the equations separately then go ahead and do so.

\displaystyle 2< x< 12

              To get \displaystyle x alone, we added \displaystyle 7 on both sides of the inequality sign

 

Example Question #51 : Algebra

\displaystyle \left | y\right | + 18 \leq 11.3

Possible Answers:

There is no solution.

\displaystyle y\geq 6.7

\displaystyle y\leq -6.7

\displaystyle y\leq 29.3

Correct answer:

There is no solution.

Explanation:

\displaystyle \left | y\right | + 18 \leq 11.3

\displaystyle \left | y\right |\leq -6.7

Because Absolute Value must be a non-negative number, there is no solution to this Absolute Value inequality.

Example Question #52 : Algebra

The weight of the bowling balls manufactured at the factory must be \displaystyle 8 lbs. with a tolerance of \displaystyle 3 lbs.  Which of the following absolute value inequalities can be used to assess which bowling balls are tolerable?

Possible Answers:

\displaystyle \left | w-3 \right | \leq 8

\displaystyle \left | w-3 \right |\geq 8

\displaystyle \left | w-8\right | \geq 3

\displaystyle \left | w-8\right | \leq 3

Correct answer:

\displaystyle \left | w-8\right | \geq 3

Explanation:

The following absolute value inequality can be used to assess the bowling balls that are tolerable:

\displaystyle \left | w-8\right |\geq3

Example Question #54 : Classifying Algebraic Functions

\displaystyle 4\left |(x+0.3)\right | - 3 < 11

Possible Answers:

\displaystyle x> 3.2 and \displaystyle x< -2.3

\displaystyle x< -3.2 and \displaystyle x> -2.3

\displaystyle x< 3.2 and \displaystyle x> -2.3

There is no solution.

Correct answer:

\displaystyle x< 3.2 and \displaystyle x> -2.3

Explanation:

\displaystyle 4\left |(x+0.3) \right | - 3< 11

\displaystyle 4x + 1.2 - 3 < 11

\displaystyle 4x -1.8< 11

\displaystyle 4x -1.8 +1.8< 11 + 1.8

\displaystyle 4x< 12.8

\displaystyle \frac{4x}{4} < \frac{12.8}{4}

\displaystyle x< 3.2

 

\displaystyle 4x + 1.2 - 3> -11

\displaystyle 4x - 1.8> -11

\displaystyle 4x - 1.8 + 1.8> -11 + 1.8

\displaystyle 4x > -9.2

\displaystyle \frac{4x}{4}>\frac{-9.2}{4}

\displaystyle x> -2.3

 

The correct answer is \displaystyle x< 3.2 and \displaystyle x>2.3

Example Question #4 : Absolute Value Inequalities

\displaystyle \left | 6+x\right |-4 < 0

Possible Answers:

\displaystyle x< 2 and \displaystyle x>10

\displaystyle x< 2 and \displaystyle x > 10

\displaystyle x>-2 and \displaystyle x< -10

\displaystyle x< -2 and \displaystyle x> -10

Correct answer:

\displaystyle x< -2 and \displaystyle x> -10

Explanation:

\displaystyle \left | 6+x\right | -4 < 0

 

\displaystyle 6 + x -4 < 0

\displaystyle 6 + x < 4

\displaystyle 6-6 + x < 4-6

\displaystyle x< -2

 

 

\displaystyle 6 + x > -4

\displaystyle 6-6 + x > -6-4

\displaystyle x>-10

 

The correct answer is \displaystyle x< -2 and \displaystyle x>-10.

 

 

 

 

Example Question #5 : Absolute Value Inequalities

\displaystyle \left | \frac{x-6}{2} \right |\leq 3

Possible Answers:

\displaystyle x\geq 0  and   \displaystyle x\leq 12

There is no solution.

\displaystyle x\leq 0 and \displaystyle x\geq12

  \displaystyle x\geq 0  and\displaystyle x\leq 12

Correct answer:

  \displaystyle x\geq 0  and\displaystyle x\leq 12

Explanation:

\displaystyle \left | \frac{x-6}{2} \right |\leq3

\displaystyle \frac{2}{1} \left | \frac{x-6}{2} \right | \leq 2\times3

\displaystyle x-6 \leq 6

\displaystyle x\leq 12

 

\displaystyle \frac{2}{1} \left | \frac{x-6}{2} \right | \geq 2 \times -3

\displaystyle x-6 \geq -6

\displaystyle x\geq 0

The correct answer is \displaystyle x\leq12  and \displaystyle x\geq 0.

Example Question #6 : Absolute Value Inequalities

\displaystyle \left | x-5\right |\leq7

Possible Answers:

\displaystyle x< 12 and \displaystyle x> -2

\displaystyle x\geq12 and  \displaystyle x\leq -2

\displaystyle x\leq12 and  \displaystyle x\geq-2

\displaystyle x\leq-12 and \displaystyle x \geq 2

Correct answer:

\displaystyle x\leq12 and  \displaystyle x\geq-2

Explanation:

\displaystyle \left | x-5\right |\leq 7

\displaystyle x-5 \leq 7

\displaystyle x-5 + 5 \leq 7 +5

\displaystyle x\leq 12

 

\displaystyle x-5 \geq -7

\displaystyle x-5 +5 \geq -7 +5

\displaystyle x\geq -2

 

The correct answer is \displaystyle x\leq12 and \displaystyle x\geq -2.

Example Question #53 : Algebra

A type of cell phone must be less than 9 ounces with a tolerance of 0.4 ounces. Which of the following inequalities can be used to assess which cell phones are tolerable? (w refers to the weight).

Possible Answers:

\displaystyle \left | w-0.4\right | \geq 9

\displaystyle \left | w-9\right | \geq 0.4

\displaystyle \left | w-0.4\right | \leq 9

\displaystyle \left | w-9\right | \leq 0.4

Correct answer:

\displaystyle \left | w-9\right | \leq 0.4

Explanation:

The Absolute Value Inequality that can assess which cell phones are tolerable is:

\displaystyle \left | w-0.4\right | \leq 9

Example Question #8 : Absolute Value Inequalities

Solve for x: \displaystyle |x-1|\le 5

Possible Answers:

\displaystyle x \le 6

\displaystyle x < 6

\displaystyle x \ge 6

\displaystyle x>6

Correct answer:

\displaystyle x \le 6

Explanation:

Step 1: Separate the equation into two equations:

First Equation: \displaystyle |x-1|\le 6
Second Equation: \displaystyle -(x-1)\ge -5

Step 2: Solve the first equation

\displaystyle x-1\le 5
\displaystyle x-1+1\le 5+1
\displaystyle x \le 6

Step 3: Solve the second equation

\displaystyle -(x+1)\ge -5
\displaystyle -x+1\ge -5
\displaystyle -x+1-1\ge -5-1

\displaystyle -x \ge -6

\displaystyle \rightarrow x \le 6

The solution is \displaystyle x\le 6

Example Question #1 : Absolute Value Inequalities

Which of the following expresses the entire solution set of \displaystyle \left | x-10\right |+ 3 < 12?

Possible Answers:

\displaystyle x>19 and \displaystyle x< -5

\displaystyle x< 1 and \displaystyle x>19

\displaystyle 1< x< 19

\displaystyle -5< x< 19

Correct answer:

\displaystyle 1< x< 19

Explanation:

Before expanding the quantity within absolute value brackets, it is best to simplify the "actual values" in the problem. Thus \displaystyle \left | x-10 \right |+3< 12 becomes:

 

\displaystyle \left | x-10 \right |< 9

 

From there, note that the absolute value means that one of two things is true: \displaystyle x-10< 9 or \displaystyle x-10>-9. You can therefore solve for each possibility to get all possible solutions. Beginning with the first:

\displaystyle x-10< 9 means that:

\displaystyle x< 19

 

For the second:

\displaystyle x-10>-9 means that:

\displaystyle x>1

 

Note that the two solutions can be connected by putting the inequality signs in the same order:

 

\displaystyle 1< x< 19

 

Learning Tools by Varsity Tutors