ACT Math : How to find absolute value

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #21 : How To Find Absolute Value

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 40

\displaystyle -82

\displaystyle 0

\displaystyle 42

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

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