Answer:
C
Step-by-step explanation:
We want to determine the vertex of the quadratic equation:

Recall that the vertex is given by the formulas:

In this case, <em>a</em> = -1, <em>b</em> = 2, and <em>c</em> = 1.
Determine the <em>x-</em>coordinate of the vertex:

To determine the <em>y-</em>coordinate, evaluate the function at <em>x</em> = 1:

In conclusion, the vertex of the quadratic equation is (1, 2).
Hence, our answer is C.
Answer:
8
Step-by-step explanation:
1. Divide the area (in square units) by Pi (approximately 3.14159).
2. Take the square root of the result. This is the radius.
3. Now double the radius to get the diameter
Because then you can replace the variables with the actual value and see of the equation is true.
Its 1/5,
35/100 - 15/100 = 20/100
for 20, 40, 60, 80, 100
1, 2, 3, 4, 5
so 20/100 = 1/5