[tex]a = \sqrt{48} - \sqrt{108} + \sqrt{192 } - \sqrt{243} + \sqrt{147} \\ a = 4 \sqrt{3} - 6 \sqrt{3} + 8 \sqrt{3} - 9 \sqrt{3} + 7 \sqrt{3} \\ a = 4 \sqrt{3} [/tex]
[tex]b = \sqrt{45} - \sqrt{80} + \sqrt{180} - \sqrt{320} + \sqrt{125} \\ b = 3 \sqrt{5} - 4 \sqrt{5} + 6 \sqrt{5} - 8 \sqrt{5} + 5 \sqrt{5} \\ b = 2 \sqrt{5} [/tex]
[tex]a \times b = 4 \sqrt{3} \times 2 \sqrt{5} = 8 \sqrt{15} [/tex]
