Помогите решить, заранее спасибо)

Ответы:

$frac{sqrt{28}-2sqrt{18}-2sqrt{12}}{6sqrt{32}+4sqrt{48}-8sqrt{7}}=frac{sqrt{7*4}-2sqrt{2*9}-2sqrt{3*4}}{6sqrt{2*16}+4sqrt{3*16}-8sqrt{7}}=\=frac{2sqrt{7}-6sqrt{2}-4sqrt{3}}{24sqrt{2}+16sqrt{3}-8sqrt{7}}=frac{2(sqrt{7}-3sqrt{2}-2sqrt{3})}{8(3sqrt{2}+2sqrt{3}-sqrt{7})}=\=frac{-2(-sqrt{7}+3sqrt{2}+2sqrt{3})}{8(3sqrt{2}+2sqrt{3}-sqrt{7})}=-frac{1}{4}$