Simplify.

a - {4b - [a - (5b - c) + 3c - (a - b - 9c) ]}

a) - a - 8b + 13c

b) a - 8b + 13c

c) a - 2b + 13c

d) - a - 2b + 13c

To simplify a - {4b - [a - (5b - c) + 3c - (a - b - 9c) ]}, we group the like terms and perform addition adn subtraction to these grouped terms. no multiplication nor division is applied. In thi case, the grouping results to

a - 4b + a - 5b + c + 3c - a + b + 9c = a - 8 b + 13c. answer is B

If you would like to simplify a - {4b - [a - (5b - c) + 3c - (a - b - 9c) ]}, you can do this using the following steps:

a - {4b - [a - (5b - c) + 3c - (a - b - 9c) ]} = a - {4b - [a - 5b + c + 3c - a + b + 9c]} = a - {4b - [ - 4b + 13c]} = a - {4b + 4b - 13c} = a - {8b - 13c} = a - 8b + 13c

The correct result would be b) a - 8b + 13c.