The graph of the function
is
- concave upward, when

- concave downward, when

Find 
1.

2.

Now:
1. when
the graph of the function is concave upward and this is for

2. when
the graph of the function is concave downward and this is for

Answer:

Step-by-step explanation:
Given

Required
Select an equivalent expression

Simplify the power

Apply law of indices:

Express decimal as fractions

Answer:
A
Step-by-step explanation:
We can see that the slope is positive, which means that the x-term must be positive.
If you expand and simply both equations into the form y = mx + b, you will find that m is positive for A and negative for B, hence A is the correct answer.
312 is the LCM for this set