first one
remember that all triangles internal angles (the 3 at the vertices) add to 180
we want BCD
we know BAD already
and ABC is a right angle
the measure of BDA is just there to throw us off
so
all adds to 180
BAD+ABC+BCD=180
59+90+BCD=180
149+BCD=180
minus 149 both sides
BCD=31
BCD=31 degrees
2nd problem
all angles add to 180 degrees
so
CAB+ABC+BCA=180
6x+147+2x+78+126+x=180
6x+2x+x+147+78+126=180
9x+351=180
minus 251 both sides
9x=-171
divide both sides by 9
x=-19
x=-19 degrees
