a)
[tex]4 {( \sqrt{3} )}^{2} = 4 \times \sqrt{3} \times \sqrt{3} = 4 \times 3 = 12[/tex]
b)
[tex] {(2 \sqrt{2}) }^{2} = 2 \sqrt{2} \times 2 \sqrt{2} = 4 \times 2 = 8[/tex]
c)
[tex] \sqrt{7} \times 3 \sqrt{7} = 3 \times 7 = 21[/tex]
d)
[tex]2 \sqrt{3} \times 5 \sqrt{3} = 10 \times 3 = 30[/tex]
