The Mathematics Knowledge subtest on the ASVAB contains a lot of questions where you're asked to solve for a variable in an algebraic equation. The best way to do this is to isolate that variable.

Practice questions

  1. Solve for x: 4x + 6 = –30

    A. –8 B. 4 C. –9 D. 9

  2. Solve for x: –10x + –23 = 23 + –8x

    A. –22 B. 23 C. –23 D. –24

Answers and explanations

  1. The correct answer is Choice (C).

    Isolate x:


  2. The correct answer is Choice (C).

    Put the variables on the same side of the equation:


    Isolate x by dividing both sides of the equation by –2:


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Angie Papple Johnston joined the U.S. Army in 2006 as a Chemical, Biological, Radiological, and Nuclear specialist, ready to tackle chemical weapons in a Level- A HAZMAT suit. She's currently the CBRN noncommissioned officer-in-charge of an aviation battalion in Washington, D.C.

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