Answer:
A) x = m - n - p
Explanation:
m - x = n + p
subtract m from both sides
m - x (- m) = n + p (- m)
m cancels out on the left and stays on the right
- x = n + p - m
divide by -1 because this is the constant in front of x
visualize as -1*x if it helps (anything multiplied by 1 is that number)
(- x / -1) = (n / -1) + (p/ -1) - (m/ -1)
the positives become negative and the negatives become positive
x = -n - p + m or x = m - n - p