Final answer:
To solve the equation, 12 = w - {-7}, we convert -{-7} to +7 and then subtract 7 from both sides to isolate w, yielding the answer w = 5.
Step-by-step explanation:
To solve the equation 12 = w - {-7}, we must isolate the variable w. First, we need to understand the notation -{-7} which is the negation of -7, thus it becomes positive 7.
The equation then simplifies to 12 = w + 7. To find the value of w, we subtract 7 from both sides of the equation.
w = 12 - 7
w = 5
To solve the equation 12 = w - (-7), we need to simplify the expression on the right side of the equation first. When we subtract a negative number, it is the same as adding the positive version of that number. So, -(-7) becomes +7.
Now we have 12 = w + 7. To isolate w, we need to subtract 7 from both sides of the equation.
12 - 7 = w
5 = w
Therefore, 12 will be equal to 5 plus -7, and the correct answer for the value of w is 5 which corresponds to option a.