58+28=86. 8+8=16 5+2=7 take the 1 from 16 and add it onto the 7 1+7=8: thats the tens place. Now we only have 6. So thats the ones place. Combine the two numbers and you get 86.
You subtract c^9 - c^14 and you get c^5 then you subtract d^-7 - d^-10 and you get d^3 because negative and a negative make a positive. so your answer is: d^3/c^5
