Option A
If f(x) =
and g(x) =
then 
<em><u>Solution:</u></em>
Given that f(x) =
and g(x) = 
To find: (f - g)(x)
We know that,
(f – g)(x) = f (x) - g(x)
Let us substitute the given values of f(x) and g(x) in above formula,

For solving the brackets in above expression,
There are two simple rules to remember:
When you multiply a negative number by a positive number then the product is always negative.
When you multiply two negative numbers or two positive numbers then the product is always positive.
So the expression becomes,

Combining the like terms,

Thus option A is correct
Step-by-step explanation:
A. Rational Number
square root 36 = 6/1
It can be write in a ratio.
They are equal so...
15x+2 = 9x+20
15x-9x = 20-2
6x =18
x = 18/6 = 3
x = 3
It will take them a total of 3.07 hours.