Answer
n = 30
Explanation
To solve for n, you have to isolate it by 'getting rid' of the 18, 2, and negative sign.
You 'remove' these numbers in backward PEMDAS.
So to 'remove' the 18, you subtract both sides by 18.
3-18 = -15
-n/2+18-18 = -n/2
So now you are left with -15 = -n/2.
To 'get rid' of the 2, you multiply each side by 2.
-15×2 = -30
-n/2×2 = -n
And now you have -30 = -n.
To 'get rid' of the negative sign, you multiply both sides by -1.
-30×-1 = 30
-n×-1 = n
So you get 30 = n or n = 30.
If you still have questions I'll answer them in the comments (under this question).
