If this is an equilateral triangle, we need half of it to find the height which is a leg of a right triangle with a hypotenuse of 15. That means that the base of this half triangle is 7.5. Use Pythagorean's Theorem to fine the height.

. x = 12.99 or 13
X+y=18
5x+y=62
x is number of five dollar bills and y is one dollar bills.
For this case we have that by definition, the point-slope equation of a line is given by:

We have the following points:

We chose a point:

Substituting in the equation we have:

Finally, the equation is: 
Answer:
OPTION C