Answer:
Option A is correct.
The given expression :
then;

Step-by-step explanation:
Given the expression: 
Cross multiplication the given expression following steps are as follow;
- Multiply numerator of the left-hand fraction by the denominator of the right-hand fraction
- Also, Multiply numerator of the right-hand fraction by the denominator of the left-hand fraction.
- then, set the two products equal to each other.
Using cross multiplication, on the given expression;

First multiply the numerator of the left hand fraction(i.e,a ) by the denominator of the right hand fraction (i,e a)
we have;

Simplify:
[1]
now, multiply numerator of the right-hand fraction( i.e, 9) by the denominator of the left-hand fraction (i.e, 4 ) in [1]
we have;

Simplify:

Therefore, the given expression is equal to: 
Answer:
It is the third one because of formula I² + 2I*II + II²
In your case I = 4x and II = 3
9=n+3
Subtract 3 on each side
n=6
Temperature changes depending on the time of the day.
Step-by-step explanation:
I hope this helps you
9=n.n
3.3=n.n
n=3