Answer:
I think thats right
Step-by-step explanation:

get rid of -2 by subtracting it from 21

Now you get your answer

Hope this helps! :)
Since there are no specific requirements given other than expression written using exponents, I am just going to give some examples.
1. 5x^2 - 3
2. 8^5 - 15x + 7
3. 15x^10 - 8x^7 + 16x^5 + 17^3 - 4^2 +13x - 2
Yk I really don’t know what to do but I’m just saying that I’m going to be gone for a while
6 1/2
First you find a common denominator. 1/4 = 3/12 and 1/3 = 4/12.
3/12 + 4/12 + 11/12 = 18/12.
18/12 = 6 6/12 = 6 1/2