I can't help you with your graphing tool. With my graphing tool, the graph looks like this.
The vertex is at (-4, -1), and it goes through the point (-3, 1).
You can divide 140 by 4 which is 35
so it would be 35 words per minute
and if you want to find out if it works with the 525 word in 15 mintues
you can do 35 ×15 = 525
All you have to do is you divide 135 by 45= 3. So, your answer would be that 135 divided by 45= 3