Answer:
see explanation
Step-by-step explanation:
Complementary angles sum to 90°
Sum the 2 angles and equate to 90
12x - 3 + 7x - 2 = 90 , that is
19x - 5 = 90 ( add 5 to both sides )
19x = 95 ( divide both sides by 19 )
x = 5
Then
mZR = 12x - 3 = 12(5) - 3 = 60 - 3 = 57°