[tex] \sqrt{3} \times \sqrt{3} - \sqrt{5} ( - \sqrt{5} ) \: + \sqrt{ {4}^{2} } = 12[/tex]
[tex]( - ) \times ( - ) = ( + )[/tex]
[tex] \sqrt{3} \times \sqrt{3} = 3[/tex]
[tex] \sqrt{5} \times \sqrt{5} = 5[/tex]
[tex] \sqrt{ {4}^{2} } = 4[/tex]
[tex]3 + 5 + 4 = 12[/tex]