## Elementary Technical Mathematics

$5x-11y-7z+3r-4s+4$
To remove parentheses when preceded by a minus sign you must change the sign of each term within the parentheses and drop the leading minus sign. Parentheses preceded by a plus sign (or implied plus sign) can be removed without changing the terms within the parentheses. $\ \ \ \$do not change the sign of any terms $\overbrace{(5x-11y-2)}\underbrace{-(7z+3)}\overbrace{+(3r+7)}\underbrace{-(4s-2)}$ $\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \$change the sign of each term