Well, little m is not the same as big M.
I will solve for big M.
M + 64 ≥ 80
M ≥ 80 - 64
M ≥ 16
What does M ≥ 16 mean?
You gotta know what the answer means. Otherwise math is dull.
It means that when the value of M is 16 or greater than 16, the original inequality is a true statement. Understand?