can someone please help me answer number 6!?! please!!

Hello there! Your answers would be:
a. 600 - 75x = y
b. 8 months
Need an Explanation?:
Part a:
Okay, so she has 600 dollars, and she has a monthly bill, but no income. This means she is not earning any money, only loosing some.
This equation will model your situation: 600 - 75x = y
This is because:
Part b:
This is asking us to see how many months it'll take for her to have $0. The question is telling us to have g(x) = 0. (This is just another way of saying y = 0, which translates to her having no money left)
So, plug 0 into the equation in place of y and solve for x.
600 - 75x = 0
Start by subtracting 600 from both sides to work to isolate x.
-75x = -600
Next, divide -600 by -75 to finish isolating x and get your answer.
X = 8
This means it will be 8 months before her checking account reaches 0.
So, these are your final answers. I hope this helps, and have a great day! Please don't hesitate to ask if you need more help with this specific question!