Engineering Board Exam Reviewer · Trigonometric Identities · hard

If x+ x= 12, find 2x.

  1. 3/4
  2. - 1/4
  3. - 3/4
  4. - 3/8

Answer

C. - 3/4

Solution

Square both sides: 2x+2 x x+ 2x= 14 1+ 2x= 14, so 2x=- 34.

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