Answer:
74 degrees
Step-by-step explanation:
The two angles in question form a straight line (180 degrees)
180 = CHF + FHD
180 = 106 + FHD
180 - 106 = FHD
FHD = 74 degrees
10ax + 5bx - 8ay - 4by = 5x(2a + b) - 4y(2a + b) = (5x - 4y)(2a + b)
option d is the correct answer.