Question 662730
If you have trouble following the steps I show, I have given a detailed explaination following these steps.


7a-4b-[5a-3{b-2(a-b)}]
7a-4b-[5a-3{b-2a+2b}
7a-4b-[5a-3{3b-2a}
7a-4b-[5a-9b+6a]
7a-4b-[11a-9b]
7a-4b-1[11a-9b]
7a-4b-11a+9b


-4a+5b   (your final answer)


Remember your order of operations first. What part of the problem do you work first? Whatever is inside the parentheses {}, which in this case is:


{b-2(a-b)}


However, there are () inside of {}.  In this case you would multiply the 2 by (a-b) first. 


{b-2a+2b}   Plug this in the original equation where {b-2(a-b)} was. This leaves you with the rest of the problem to solve.


7a-4b-[5a-3{b-2a+2b]    Now solve what is inside the brackets [].


7a-4b-[5a-3b+6a-6b]


Combine like terms inside the [] leaving:


7a-4b-[11a-9b]


Now drop the brackets and combine like terms.  Be sure to distribute the negative sign (-) after the 4b before dropping the brackets.


7a-4b-[11a-9b]
7a-4b-11a+9b
-4a+5b      (answer)


Please ask if have any questions.  :)