Answer:
81
Explanation:
Any number, wether it is negative or postive, will always be postive when there is a even exponent.
In this case, we have a -9, and a exponent thats 2.
Since 2 is a even number, -9^2 will be a postive value.
Now, what is the actual value of this?
Well, a exponent of 2 basiclly means 2 numbers being multiplied together.
Or in this case, 2 negative 9s being multiplied together.
THis will be:
-9*-9
=
As I said above, a even exponent makes a negative number postive.
You see here that a negative 9 is being multiplied by -9. When two negative numbers multiply together, they make a postive.
THis is why a even exponent makes a postive.
Hope this helps!