Given:
The given value is [tex]-a[/tex].
To find:
The multiplicative inverse of [tex]-a[/tex].
Solution:
We know that [tex]y[/tex] is the multiplicative interval of [tex]x[/tex] if [tex]xy=1[/tex].
Let [tex]x[/tex] be the multiplicative inverse of the given value [tex]-a[/tex]. Then,
[tex](-a)\times x=1[/tex]
Divide both sides by [tex]-a[/tex].
[tex]x=\dfrac{1}{-a}[/tex]
[tex]x=-\dfrac{1}{a}[/tex]
Therefore, the multiplicative inverse of [tex]-a[/tex] is [tex]-\dfrac{1}{a}[/tex]. Hence the correct option is A.