Given:
Polynomials
To find:
Monomial of 2nd degree with leading coefficient 3
Solution:
Monomial is an algebraic expression with only one term.
Option A: 
It is not a monomial because it have 2 terms.
It is not true.
Option B:
It is not a monomial because it have 2 terms.
It is not true.
Option C: 
It have one term only. So, it is a monomial.
Degree means highest power. So degree = 2
Leading coefficient means the value before variable.
Leading coefficient = 3
It is true.
Option D: 
It have one term only. So, it is a monomial.
Degree means highest power. So degree = 3
It is not true.
Therefore
is a monomial of 2nd degree with a leading coefficient of 3.
We have to solve x in terms of a, b and c:
a x - 3 b = c
a x - 3 b + 3 b = c + 3 b
a x = c + 3 b
x = ( c + 3 b ) : a
Answer:
4 ) ( c + 3 b ) / a
-4/7 (decimal form (.571))
-4+3x= 2x +3x +3
-4-3= 2x + 3x -3x
-7 =2x
X= -7/2