Question 18481
adding and subtracting is different then flip flopping numbers (recipricals)
The inverse of adding -5.2 will be subtracting -5.2 
Which is +(-5.2) and can be simplified as -5.2

Flipping numbers are for multiplication and division.
2n=8
Now you need to flip the number of 2, which is 1/2.
2n(1/2)=8(1/2)
n=4