Question

Помогите решить 4,5 плиз

Answer 1

$frac{a}{Sin alpha }= frac{b}{Sin beta }\\ a= frac{b*Sin alpha }{Sin beta }= frac{24* frac{1}{12} }{ frac{1}{7} }=2*7=14\\\( sqrt{11} - sqrt{5})( sqrt{11} + sqrt{5})=( sqrt{11}) ^{2}-( sqrt{5}) ^{2} =11-5=6$