First, I will distribute the numbers outside of parentheses to the numbers inside of the parentheses: (32m-28n) + (18n-24m)
Next, I will take out the parentheses: 32m-28n+18n-24m
After that, I will combine all of the numbers with the m variable: 32m-28n+18m-24m 32m+18m 50m
Lastly, I will combine all of the numbers with n as a variable, treating both like negative numbers because there is a subtraction sign before them. 50m-28n-24n -28n-24n -52n
This ends with this expression: 50m-52n
Let me know if you need any clarifications or anything :)