You only need one of them:
(135 mile²) x (5,280 feet/mile)²
= (135 mile²) x (27,878,400 feet²/mile²)
= (135 x 27,878,400) mile² - feet² / mile²
= 3,763,584,000 feet²
21 - 4x = 108
<em><u>Subtract 21 from both sides</u></em>
-4x = 87
<em><u>Divide both sides by -4</u></em>
x = -21.75
Polynomials are linear combinations of positive integer powers. For example,

is a polynomial, but

is not.
(In case you're unfamiliar with the term, a linear combination of two quantities is the sum of scaled versions of those quantities, e.g. a general linear combination of
and
is
, where
are any numbers.)
is not a polynomial; the offending term is
, or
.
Answer:
value of x is for values that are excludedor or left out