Tameeka tells Marcus, "When you add 16 to my mystery number then subtract 20, you get the same result as when you add my mystery number to itself, then add 20 and subtract 16.” What is Tameeka’s mystery number?
Write and solve an equation to represent this situation.
m + 16 - 20 = m - 4
m + m + 20 - 16 = 2 m + 4
so
2 m + 4 = m -4
m = -8