Of means multiplication
So

And then simplify the numerator ad denominator
=

And simplify the numerator and denominator again
=

And we are finally left with the answer which is
Less then i really hope i helped
Answer:
y=90x+2,000
Step-by-step explanation:
90 is the rate of change because the hot air balloon descends 90 feet per minute.
And 2,000 is the starting point because the hot air balloon started the descent at 2,000 feet.