1. Use the exterior angle theorem that states that an exterior angle in a triangle is equal to its two remote interior angles.
x+46=84
x=38 degrees
2. There are two parallel lines cut by transversal. We can see a same side interior relationship.
3x-5+90+2x=180
5x=95
x=19 degrees
3. Use exterior angle theorem again.
90+34=x+72
x=52 degrees