Answer:
81(x + 2y)(x - 2y)
Step-by-step explanation:

w represents width
4w represents length
d represents diagonal
w2 + (4w)2 = d2
w2 + 16w2 = d2
17w2 = d2
±w√17 = d
The diagonal is the width times √17.
So it decreases by 11% which means by the next year it's worth 89% of the original price, write 89% like a decimal. then put it to the power of 4 (4 years) and multiply by the original number
.89 ^ 4 * 12250 = 7685.92
Outcome
Hope this helps :)