Answer:
∠b = 88 - 5x
Step-by-step explanation:
If a and b are complementary, then sum of two angles is 90
∠a + ∠b = 90
5x + 2 + ∠b = 90
∠b = 90 - 5x - 2
B
0.3 is the answer to 3/10 as a decimal