The answer is correct because it would have to go like this;
(-4x + 9)² = (-4x + 9)(-4x + 9)
hope this helps, God bless!
Jenny started with 20 markers
her sister gave her 64
Given :
AT&T charges $350 to get a plan with them, plus $60 per month.
T-Mobile charges a $275 initial fee, plus $80 per month.
To Find :
Write an equation or inequality that can be used to determine the number of months it would take for T-Mobile to cost the same or more than AT&T.
Solution :
Money-time relation of plan AT&T :

Money-time relation of plan T-Mobile :

( Here, x and y are number of months )
Let, after t months would take for T-Mobile to cost the same or more than AT&T.
So, 

Hence, this is the required solution.
a)September because in absolute value it is the least amount.
b)August because it is the only one that lost below 190k.