Write down the coefficient of the following: $ - x$.

Hint: In this question we have to determine the coefficient of $ - x$ . So first of all we have to understand the definition of coefficient. We can also say that the coefficient is a multiplicative term or factor in some term of a series, polynomial like ${x^2},{a^3},{y^3},{b^2}...$ or in any expression, equations.

Complete step by step answer:
Let us understand coefficients first: A number which is used to multiply a variable that can be $a,b,c,x,z...$ etc. is known as the coefficient of that number. We know that the variables appearing in the coefficient are called parameters and those parameters must be distinguished from the other variables. As explained in the hint we have to look for the multiplicative term in the expression, so we can write $ - x$ also as :
$ - 1 \times x$ .
Here $ - 1$ is multiplied with $x$ .

Hence the coefficient of $ - x$ is $ - 1$.

Note: We should note that if there is no number in the variable, then the coefficient of that given number is $1$ . If we have an algebraic expression of the form $a{x^3} + b{x^2} + cx + d$ , then we can say that the coefficient of ${x^3}$ is $a$, the coefficient of ${x^2}$ is $b$ and the coefficient of $x$ is $c$.