SSAT Upper Level Math : How to find absolute value

Study concepts, example questions & explanations for SSAT Upper Level Math

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Example Questions

Example Question #45 : Algebra

\(\displaystyle \left | -2^{3} + 3 (4^{2})\right |\)

Possible Answers:

\(\displaystyle 16\)

\(\displaystyle -40\)

\(\displaystyle 40\)

\(\displaystyle -16\)

Correct answer:

\(\displaystyle 40\)

Explanation:

The first step to solving is to use the Order of Operations.

\(\displaystyle \left |-8 + 3 (16) \right |\)

\(\displaystyle \left | -8 +48 \right |\)

The absolute value \(\displaystyle \left | x\right |\) of a real number x is the non-negative value of x without regard to its sign.  The absolute value of a number is the distance of that number from the point of origin or zero on a number line.

\(\displaystyle \left | 40\right | = 40\)

 

 

Example Question #42 : Algebra

\(\displaystyle 3 \left | \frac{1}{2} x +2\right | > 12\)

Possible Answers:

\(\displaystyle x>4\)  and \(\displaystyle x< -12\)

\(\displaystyle x>4\) and \(\displaystyle x< 12\)

\(\displaystyle x< 4\) and \(\displaystyle x>12\)

\(\displaystyle x < 4\) and \(\displaystyle x> -12\)

Correct answer:

\(\displaystyle x>4\)  and \(\displaystyle x< -12\)

Explanation:

To solve this Absolute Value inequality, remove the Absolute Value bars and create two linear inequalities.

\(\displaystyle 3 (\frac{1}{2}x) + 6> 12\)

\(\displaystyle 3 (\frac{1}{2}x) + 6 < -12\)

Then, using the Order of Operations and the method for solving multi-step equations solve.

First inequality:

\(\displaystyle 3 (\frac{1}{2}x) + 6> 12\)

\(\displaystyle \frac{3}{2}x + 6 > 12\)

\(\displaystyle \frac{3}{2}x + 6 - 6 >12 -6\)

\(\displaystyle \frac{3}{2}x >6\)

\(\displaystyle \frac{3}{2}x (\frac{2}{3}) >\frac{6}{1} (\frac{2}{3})\)

\(\displaystyle x> 4\)

 

Second inequality:

\(\displaystyle \frac{3}{2}x +6 < -12\)

\(\displaystyle \frac{3}{2}x +6 -6 < -12 -6\)

\(\displaystyle \frac{3}{2}x < -18\)

\(\displaystyle \frac{3}{2}x (\frac{2}{3}) < -\frac{18}{1} (\frac{2}{3})\)

\(\displaystyle x< -12\)

 

The solution to  \(\displaystyle 3\left | \frac{1}{2}x +2 \right | > 12\) consists of the two intervals \(\displaystyle x > 4\) and  \(\displaystyle x < -12\).  This pair of inequalities is the solution.

 

Example Question #43 : Algebra

\(\displaystyle \left |4x + 4 \right | < 16\)

Possible Answers:

\(\displaystyle x< -3\) and  \(\displaystyle x> -5\)

\(\displaystyle x>3\) and \(\displaystyle x< -5\)

\(\displaystyle x < 3\) and \(\displaystyle x> -5\)

\(\displaystyle x < 3\) and \(\displaystyle x = 5\)

Correct answer:

\(\displaystyle x < 3\) and \(\displaystyle x> -5\)

Explanation:

To solve this Absolute Value inequality, remove the Absolute Value bars and create two linear inequalities.

\(\displaystyle 4x + 4 < 16\) and

\(\displaystyle 4x + 14 > -16\)

Then solve each of the inequalities.

First inequality:

\(\displaystyle 4x + 4 < 16\)

\(\displaystyle 4x +4 - 4 < 16-4\)

\(\displaystyle 4x < 12\)

\(\displaystyle \frac{4x}{4} < \frac{12}{4}\)

\(\displaystyle x < 3\)

Second inequality:

\(\displaystyle 4x + 14> -16\)

\(\displaystyle 4x + 4 -4 > -16-4\)

\(\displaystyle 4x > -20\)

\(\displaystyle \frac{4x}{4}> \frac{-20}{4}\)

\(\displaystyle x> -5\)

 

The solution to   consists of the two intervals \(\displaystyle x< 3\) and  \(\displaystyle x > -5\).  This pair of inequalities is the solution.

Example Question #21 : How To Find Absolute Value

\(\displaystyle \left | 7x\right |\geq28\)

Possible Answers:

\(\displaystyle x\leq 4\) and \(\displaystyle x \geq -4\)

\(\displaystyle x\geq 7\) and \(\displaystyle x\leq -7\)

\(\displaystyle x\leq-4\) and \(\displaystyle x\geq 4\)

\(\displaystyle x\leq 7\) and \(\displaystyle x\geq -7\)

Correct answer:

\(\displaystyle x\leq-4\) and \(\displaystyle x\geq 4\)

Explanation:

To solve this Absolute value inequality, remove the absolute value bars and create two linear inequalities and solve.

\(\displaystyle 7x\geq 28\)

\(\displaystyle x\geq4\)

\(\displaystyle 7x \leq -28\)

\(\displaystyle x \leq -4\)

 

The solution to \(\displaystyle \left | 7x\right | \geq 28\) consists of the two intervals \(\displaystyle x\geq4\) and  \(\displaystyle x \leq -4\).

This pair of inequalities is the solution.

Example Question #47 : Algebra

\(\displaystyle -\left |-8- 2 (5-2)^{2} \right |\)

Possible Answers:

\(\displaystyle 26\)

\(\displaystyle -44\)

\(\displaystyle 44\)

\(\displaystyle -26\)

Correct answer:

\(\displaystyle -26\)

Explanation:

Step One: Order of Operations

\(\displaystyle -\left |-8 - 2 x 3^{2} \right |\)

\(\displaystyle -\left | -8-2x9\right |\)

\(\displaystyle -\left | -8-18\right |\)

\(\displaystyle -\left | -26\right |\)

The absolute value of \(\displaystyle -26\) is \(\displaystyle 26.\)  However, because there is a negative sign outside the Absolute value bars, you would multiply the \(\displaystyle 26\) by \(\displaystyle -1\) to get the solution.

The correct answer is \(\displaystyle -26\)

Example Question #21 : How To Find Absolute Value

Micah is seeking new employment. The salary that he desires must be $4,000 per month with a tolerance of $600.  Which absolute value inequality can be used to assess the salary which will be tolerable?

Possible Answers:

\(\displaystyle \left | s-4000\right | \leq 600\)

\(\displaystyle \left | s-600\ \right | \leq 4,000\)

\(\displaystyle \left | s-4000\right |\geq 600\)

\(\displaystyle \left | s-600\right |\geq 4,000\)

Correct answer:

\(\displaystyle \left | s-4000\right | \leq 600\)

Explanation:

\(\displaystyle \left | s-4000\right | \leq 600\) is the correct solution.

This absolute value inequality states that the difference between the salary of $4,000 must be less than or equal to $600 to be tolerable.

Example Question #22 : Absolute Value

In order to ride the roller coaster at the local amusement park, children must be \(\displaystyle 145cm\) tall with a tolerance of \(\displaystyle 5cm.\) Which of the following absolute value inequalities can be used to assess which heights will be tolerable?

Possible Answers:

\(\displaystyle \left |h-145 \right | \geq 5\)

\(\displaystyle \left | h-145\right | \leq 5\)

\(\displaystyle \left | h-5\right |\leq 145\)

\(\displaystyle \left | h-5\right | \geq 145\)

Correct answer:

\(\displaystyle \left | h-145\right | \leq 5\)

Explanation:

\(\displaystyle \left | h-145\right | \leq 5\) is the correct solution.

This Absolute Value inequality states that the difference between the children's height and \(\displaystyle 145cm\) must be less than or equal to \(\displaystyle 5cm\).

Example Question #23 : Absolute Value

Using \(\displaystyle < , >, or =\) compare the following absolute value.

 

\(\displaystyle \left | -9\right |\) __________\(\displaystyle \left | -7\right |\)

Possible Answers:

\(\displaystyle \left | -9\right |\leq \left | -7\right |\)

\(\displaystyle \left | -9\right |=\left | -7\right |\)

\(\displaystyle \left | -9\right |< \left | -7\right |\)

\(\displaystyle \left | -9\right |> \left | -7\right |\)

Correct answer:

\(\displaystyle \left | -9\right |> \left | -7\right |\)

Explanation:

The absolute value of a number is its distance from zero. The absolute value of a negative integer is a positive integer. The distance from  zero to \(\displaystyle -9\) on a number line is \(\displaystyle 9\), so

\(\displaystyle \left | -9\right | = 9\) 

The absolute value of a number is its distance from zero. The absolute value of a negative integer is a positive integer. The distance from 0 to \(\displaystyle -7\)on a number line     is \(\displaystyle 7\). Therefore:

\(\displaystyle \left | -7\right | = 7\) 

Therefore

\(\displaystyle \left | -9\right |> \left | -7\right |\)

because

\(\displaystyle 9>7\)

Example Question #182 : Integers

Evaluate the expression if \(\displaystyle x=5\) and \(\displaystyle y=7\).

\(\displaystyle \left | 4x+3y \right | - \left | 4x-3y \right |\)

Possible Answers:

\(\displaystyle -82\)

\(\displaystyle 42\)

\(\displaystyle 40\)

\(\displaystyle 0\)

\(\displaystyle 82\)

Correct answer:

\(\displaystyle 40\)

Explanation:

\(\displaystyle \left | 4x+3y \right | - \left | 4x-3y \right |\)

To solve, we replace each variable with the given value.

\(\displaystyle \left | 4 (5) +3 ( 7) \right | - \left | 4 (5) -3 ( 7) \right |\ .\)

\(\displaystyle \left | 20 +21 \right | - \left | 20 -21 \right |\)

Simplify. Remember that terms inside of the absolute value are always positive.

\(\displaystyle \left | 41 \right | - \left | -1 \right |=41-1 = 40\)

Example Question #22 : How To Find Absolute Value

Evaluate: \(\displaystyle \begin{vmatrix}\; \; \left | 5- 3 \cdot 4\right |-8 \right \;\end{vmatrix}\)

Possible Answers:

\(\displaystyle 9\)

\(\displaystyle 1\)

\(\displaystyle 5\)

\(\displaystyle 11\)

\(\displaystyle 15\)

Correct answer:

\(\displaystyle 1\)

Explanation:

 \(\displaystyle \begin{vmatrix}\; \; \left | 5- 3 \cdot 4\right |-8 \right \;\end{vmatrix}=\begin{vmatrix}\; \; \left | 5- 12\right |-8 \right \;\end{vmatrix}=\begin{vmatrix}\; \; \left | -7\right |-8 \right \;\end{vmatrix}=| 7 - 8| = | -1| = 1\)

 

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