1. 3/4
2. im not sure if it means after taking away 3/4, but if it is, its 10/4
x=10/4 and -30/4 i believe, im not too good with fractions, sorry if its wrong :((
Answer:
z = 86
Explanation:
90 - 68 = 12
180 - 78 = 102
102 + 12 = 114
180 - 114 = 86
Current value of the boat = $45000
Rate at which the value decrease = 8.5%
Value decreased after 1 year = 
Hence, value becomes = 
Value decreased after 2nd year =

Hence, value becomes = 
Value decreased after 3 year =

Hence, value becomes = 
So, value of the boat after 3 years becomes $34472.74