So basically you want to isolate only one of the variable on one side so
y=-9+x^2
add 9 to both sides
y+9=x^2
square root both sides

x=
D. because for every hour it goes down 5 degrees and since there is a 1 hour gap in between 7 am and 9 am
Answer: The first option
Step-by-step explanation:
I'm smart
Answer: 6x^2
Step-by-step explanation: