Y = -2x - 1
y = 3 - x - 1......y = 2 - x
2 - x = -2x - 1
-x + 2x = -1 + 2
x = 1 <==
Answer: 
Step-by-step explanation:
Given : Hot air balloons generally descend at a rate of 200 to 400 feet per minute.
Also, Four balloons descend 200 feet per minute for 9 minutes.
Then, the total change in altitude for all 4 balloons will be :-

Hence, the total change in altitude for all 4 balloons will be : Balloon descends 18 feet in 4 minutes.
The format of a line equation is y = mx + b
When two lines are parallel, their 'm' variables are equal.
Knowing this, the unknown line equation, so far, would look like this:
y = 9x + b
Since we know that the line equation goes through the point (2, 7)
7 = 18 + b
b = -11
y = 9x - 11