He sells it at $80 which gives him a profit of $5!
On the X-Y plane, the points p and r are on the vertical line X=x. Then the perpendicular (horizontal) line through p will have the equation Y=y. Points q on that line will have coordinates
... q(<anything>, y)
I think the answer is 156, I got this by multiplying 12 times 13.
<span>Simplifying
x + -1.4 = 7.82
Reorder the terms:
-1.4 + x = 7.82
Solving
-1.4 + x = 7.82
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '1.4' to each side of the equation.
-1.4 + 1.4 + x = 7.82 + 1.4
Combine like terms: -1.4 + 1.4 = 0.0
0.0 + x = 7.82 + 1.4
x = 7.82 + 1.4
Combine like terms: 7.82 + 1.4 = 9.22
x = 9.22
Simplifying
x = 9.22</span>
