For all of these you're trying to solve for the variable. The variable is usually a number or symbol.
11) -44+n=36
Step one would be to add 44 to both sides of the equation.
N=80
12) -36=p-91
Step one would be to add -91 to both sides of the equation.
P=55
13) X-225=671
Step one you be to add 225 to both sides of the equation. Although it may seem difficult because of the big numbers, it's the same technique.
14) 19=c-(-12)
Step one on this equation will be a little different. Because there are two negative signs (-), they turn into a plus sign. Remember, two negative signs make a positive sign.
19=c+12
Now you just subtract 12 from each side of the equation.
6=C