If sin (12x + 18) ° = cos (3. x - 3), find the value of x.

x = 5

Step-by-step explanation:

Using the cofunction identity

sin x = cos (90 - x), then

12x + 18 = 90 - (3x - 3), that is

12x + 18 = 90 - 3x + 3 (add 3x to both sides)

15x + 18 = 93 (subtract 18 from both sides)

15x = 75 (divide both sides by 15)

x = 5