Respuesta :

Answer:

Value of x = 25

Step-by-Step Explanation:

~ Knowing that, in a right triangle ~

sin(40-x)=cos(3x) ⇒

sin(40-x)=sin(90-3x) ⇒

40 - x = 90 - 3x ⇒

40 - x  +3x=90 - 3x  +3x =>

40+2x=90 =>

2x=50 =>

x = 25

Now it is proven to be that,

x = 25