Answer:
(-1, 4)
Step-by-step explanation:
Use of the coordinate plane.
The vertex of the parabola is 1 to the left and up 4.
Think of the vertex as where the curve starts.
Let x be the amount each friend pays
.
There are five friends contributing ,so
5x will be the total money collected
.
It needs to equal the price plus the tax, 210 + 15
= 225
So the equation becomes,

5x = 225
dividing right side by 5, we have
x = 225/5 = 45
Answer: So each frien pays $45.
The answer is 88 cube units.