Least to greatest 2/3, 3/5, 13/15, 2/5

2/5 3/5 2/3 13/15

Step-by-step explanation:

2/3, 3/5, 13/15, 2/5

The least common denominator is: 15.

Rewriting as equivalent fractions with the LCD:

10/15, 9/15, 13/15, 6/15

Ordering these fractions by the numerator in order from least to greatest:

6/15 < 9/15 < 10/15 < 13/15

Therefore, your input in order from least to greatest is:

2/5 < 3/5 < 2/3 < 13/15

The vertex form of a quadratic function:
(h,k) - the coordinates of the vertex 

If a>0, then the parabola opens upwards, so the vertex is the minimum of the function.
If a<0, then the parabola opens downwards, so the vertex is the maximum of the function.

a=-1<0
the vertex is maximum

a=1>0
the vertex is minimum