Answer: 81
To get this answer, you do two things
1) Take half of the x coefficient 18 to get 9
2) Square the result from the previous step to get 9^2 = 9*9 = 81
This value is added on to get x^2+18x+81 which factors to (x+9)^2 confirming we have a perfect square trinomial
Let's represent the number of weeks with the variable 'w':
130 + 25w = 600
We subtract both sides by 130:
25w = 470
w = 18.8
We round up:
It will take her 19 weeks.
The negative infinity for the x coordinate states that the graph should move to the bottom and the y coordinate is positive infinity so that the graph goes up
the first graph is your answer