Perform the operations left parenthesis negative 5 m squared

Perform the operations. left parenthesis negative 5 m squared plus 6 n squared minus 4 n right parenthesis minus left bracket left parenthesis 6 m squared minus 4 m plus 2 n right parenthesis plus left parenthesis negative 6 m squared right parenthesis plus 4 n squared right bracket(5m2+6n24n)[(6m24m+2n)+(6m2)+4n2]

Solution

{ -5m² + 6n² -4n } - [ { 6m² - 4m + 2n}+ { -6m² } + 4n² ] = - 5m² + 6n² - 4n -( 6m² - 4m + 2n) - ( - 6m²) - 4n² = - 5m² + 6n² - 4n - 6m² + 4m - 2n + 6m² - 4n² = m² ( - 5 -6 + 6)  + n² ( 6 - 4) + 4m - n ( 4 + 2) = - 5m² + 2n² + 4m - 6n