Answer:
45 cents
Step-by-step explanation:
X-intercept: none
Y-intercept: -3/2
1) graphs y = -9x + 12 and y = 1/3x - 12 are not coincident.
2) The graphs are not parallel, because the angular coefficients are not equal
3) The condition of perpendicularity:
, where 
- not perpendicular
If Tim had $20 to spend on 6 pens, and after buying them he had $8 left, that means that he spent 20 - 8 = $12 dollars on those 6 pens.
This means that to calculate the price of one pen, you just need to divide the money he spent ($12) by the number of pens he bought (6), and that is 12/6 = 2. Each pen cost him <span>$2.</span>
Eighteen times twelve is 216... if that's what you're asking...