Answer:
B
Step-by-step explanation:
Using the cofunction identity
sin x = cos(90 - x)
Given
sin(3x + 19) = cos(5x - 25), then
3x + 19 = 90 - (5x - 25)
3x + 19 = 90 - 5x + 25
3x + 19 = 115 - 5x ( add 5x to both sides )
8x + 19 = 115 ( subtract 19 from both sides )
8x = 96 ( divide both sides by 8 )
x = 12 → B
