Question

why -(-m square+5mn)= m square-5mn

Answer 1

$- ( - {m}^{2} + 5mn )= {m}^{2} - 5mn \\ {m}^{2} - 5mn = {m}^{2} - 5mn \\ \\ \\ As \: there \: the \:variables \: (or \: terms)\: are \: to \: be \: multiplied \\ \: with \: minus \: their \: sign \: got \: changed$

$- \times - = + \\ - \times + = - \\ + \times + = + \\ + \times - = -$

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