Answer
A. Subtraction
Work Step by Step
In order to solve this algebraic expression, we must isolate the variable. A variable is the letter in the problem (for instance, in the equation x+2=10, x is the variable). Because addition and subtraction are inverse operations (they cancel each other out), we know we must add when a number is being subtracted from the variable and subtract when a number is being added to the variable. In the expression 14+c=39, 14 is being added to c, so we know we must subtract to isolate the variable, c. When we subtract 14 from each side, we obtain that c=25.
