First of all, you can simplify the 4 at the numerator and the 14 at the denominator (they're both multiple of 2):

Now, rationalize a denominator means that you have to get rid of the square root, in order to have an integer denominator.
To do so, remember that you can always multiply any number by 1 without changing its value, and you can always think of 1 as a fraction where numerator and denominator are equal:

Answer:
C
Step-by-step explanation:
Probably it's all wrong
4.5 = 10 %If is the same then 4.5*20+45=135
If not then
FV=P(1+r)n45* (1+0.1)20 = 45*6.727=302.737
Answer:
The following are the solution to the given points:
Step-by-step explanation:
for point A:


The set A is not part of the subspace 
for point B:


The set B is part of the subspace
for point C:

In this, the scalar multiplication can't behold

∉ C
this inequality is not hold
The set C is not a part of the subspace
for point D:

The scalar multiplication s is not to hold
∉ D
this is an inequality, which is not hold
The set D is not part of the subspace 
For point E:

The
is the arbitrary, in which
is arbitrary

The set E is the part of the subspace
For point F:

The
arbitrary so, they have
as the arbitrary 
The set F is the subspace of 