Question

1) √ 21 /√12 = 2) √ 12-3√ 3 =

Answer 1

1) √ 21 /√12 =√21/12=√7/4=√7/2
2) √ 12-3√ 3 =2√3-3√3=-√3

Answer 2

$\frac{ \sqrt{21} }{ \sqrt{12} } = \frac{ \sqrt{3*7} }{ \sqrt{3*4} } = \frac{ \sqrt{3} \sqrt{7} }{ \sqrt{3} \sqrt{4} } = \frac{ \sqrt{7} }{ 2 }$

$\sqrt{12} -3 \sqrt{3} = \sqrt{4*3} -3 \sqrt{3} =2 \sqrt{3} -3 \sqrt{3} =- \sqrt{3}$