Which of the following is a solution to 2cos2x − cos x − 1 = 0? a. 0° b. 150° c. 180° d. 210°

The correct answer option is A. 0°.

Step-by-step explanation:

We are given a quadratic equation in cos which is factored in the same way like usual quadratic equation is factored:

This can be factorized and can also be written as:

or

or

or

or

Therefore, the correct answer option is A. 0°.

20

Step-by-step explanation:

Hope this helps