Answer:
d
Step-by-step explanation:
Supplementary angles sum to 180°
Sum the angles A and B and equate to 180m that is
16x - 7 + 21x + 2 = 180
37x - 5 = 180 ( add 5 to both sides )
37x = 185 ( divide both sides by 37 )
x = 5
Thus
∠ A = 16x - 7 = 16(5) - 7 = 80 - 7 = 73° → d