(a) What is the exact value of cos 510˚

The answer to your question is cos 510 = -

Step-by-step explanation:

Data

cos 510° = ?

Process

1.- Find an equivalent angle to 510° subtracting 360°

          510 - 360 = 150°

That means that if we calculate the cos 150 will be the same as cos 510

2.- Calculate the cos 150°

150° is located in the second quadrangle. In this quadrangle cosine is negative.

Also, cos 150° = 180° - 30°

If we calculate the cosine of angle 30° will be the same value of cos 150° and the same of cos 510° but with negative sign.

         cos 30° =    cos 150° =    and  cos 510° =

2(2x + 3) = -4 + 2(2x + 5)

4x + 6 = -4 + 4x + 10

4x + 6 = 4x + 6

4x - 6 + 6 = 4x - 6 + 6

4x = 4x

x = x

unlimited solutions.