# Thread: A problem with sketching lines on the graphic calculator.

1. ## A problem with sketching lines on the graphic calculator.

I have just changed courses - from Math 10 to Math 20 - and it's hard to get used to it. The problem is the following.

The equation C=50w+300 could be used to model the cost of running the business, where w is the number of weeks and C is the cost in dollars.
The equation M=150w could be used to model the earnings, where w is the number of weeks and M is the money earned in dollars.
-On the calculator, sketch both lines so that you can clearly see where they intersect. Determine the intersection. Explain what this point means in relation to the business.

What I did was
C=M
50w+300=150w
w=3 (The intersection. The business starts making a profit after 3 weeks.)
But how do I sketch the lines?

2. Originally Posted by Eloise1995
I have just changed courses - from Math 10 to Math 20 - and it's hard to get used to it. The problem is the following.

The equation C=50w+300 could be used to model the cost of running the business, where w is the number of weeks and C is the cost in dollars.
The equation M=150w could be used to model the earnings, where w is the number of weeks and M is the money earned in dollars.
-On the calculator, sketch both lines so that you can clearly see where they intersect. Determine the intersection. Explain what this point means in relation to the business.

What I did was
C=M
50w+300=150w
w=3 (The intersection. The business starts making a profit after 3 weeks.)
But how do I sketch the lines?
Hi Eloise1995,

3. graphed on a TI-83+

4. Thank you so much! It does seem very simple, now.
But how did determine the values for WINDOW?