The coefficient of first term of a polynomial written in standard (descending order) form is called the coefficient ?

We know that

1) The degree of a polynomial is the highest degree of its terms
2) The leading term in a polynomial is the highest degree term
3) The leading coefficient of a polynomial is the coefficient of the leading term  
Therefore

The coefficient of first term of a polynomial written in standard (descending order) form is the coefficient of the leading term, thus is called the leading coefficient.

  the answer is
The leading coefficient 

The answer is: "leading".

 Therefore, the complete sentence is: "The coefficient of first term of a polynomial written in standard (descending order) form is called the leading coefficient".

 For example, if you have the following polynomial:

 2x²-5x+10=0

 Then, as you can see, the leading coefficient is: 2

The domain is all real numbers greater than or equal to -1because sqrt(x+5)-2 need to be greater than or equal to 0, we have sqrt(x+5) greater than or equal to 2.square both sides, and minus 5 from both sides, we arrive at the conclusion