a)
[tex]2 \sqrt{8} \times 4 \sqrt{3} = 8 \sqrt{8 \times 3} = 8 \sqrt{24} = 8 \sqrt{4 \times 6} = 8 \times 2 \sqrt{6} = 16 \sqrt{6} [/tex]
b)
[tex]4 \sqrt{3} \times 5 \sqrt{15} = 20 \sqrt{3 \times 15} = 20\sqrt{45} = 20 \sqrt{9 \times 5} = 20 \times 3 \sqrt{5} = 60 \sqrt{5} [/tex]
c)
[tex]3 \sqrt{5} \times 4 \sqrt{7} = 12 \sqrt{5 \times 7} = 15 \sqrt{35} [/tex]
d)
[tex]2 \sqrt{3} \times 3 \sqrt{5} = 6 \sqrt{3 \times 5} = 6 \sqrt{15} [/tex]
