Chú ý: Để đảm bảo quyền lợi và bảo vệ tài khoản của mình
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HomeLớp 9Toán lớp 9 - Sách Kết nối tri thứcBài 8. Khai căn bậc hai với phép nhân và phép chiaBài tập nâng cao
{"common":{"save":0,"post_id":"7795","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"7420","post_id":"7795","mon_id":"1159278","chapter_id":"1159327","question":"<p>Tr\u1ee5c c\u0103n \u1edf m\u1eabu c\u1ee7a bi\u1ec3u th\u1ee9c <span class=\"math-tex\">$B=\\dfrac{3+4\\sqrt{3}}{\\sqrt{6}+\\sqrt{2}-\\sqrt{5}}$<\/span> và rút g\u1ecdn ta \u0111\u01b0\u1ee3c:<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$\\sqrt{6}+\\sqrt{2}-\\sqrt{5}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$\\sqrt{6}+\\sqrt{2}+\\sqrt{5}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$\\sqrt{6}-\\sqrt{2}-\\sqrt{5}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$\\sqrt{6}-\\sqrt{2}+\\sqrt{5}$<\/span>"],"correct":"2","level":"3","hint":"<p><span class=\"math-tex\">$B=\\dfrac{3+4\\sqrt{3}}{\\sqrt{6}+\\sqrt{2}-\\sqrt{5}}$<\/span> Nhân c\u1ea3 t\u1eed s\u1ed1 và m\u1eabu s\u1ed1 v\u1edbi <span class=\"math-tex\">$\\sqrt{6}+\\sqrt{2}+\\sqrt{5}$<\/span><\/p><p><span class=\"math-tex\">$B=\\dfrac{(3+4\\sqrt{3})(\\sqrt{6}+\\sqrt{2}+\\sqrt{5})}{(\\sqrt{6}+\\sqrt{2}-\\sqrt{5})(\\sqrt{6}+\\sqrt{2}+\\sqrt{5})}$<\/span><\/p>","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B.<\/strong> <span class=\"math-tex\">$\\sqrt{6}+\\sqrt{2}+\\sqrt{5}$<\/span><\/span><\/p><p><span class=\"math-tex\">$B=\\dfrac{3+4\\sqrt{3}}{\\sqrt{6}+\\sqrt{2}-\\sqrt{5}}$<\/span><\/p><p><span class=\"math-tex\">$B=\\dfrac{(3+4\\sqrt{3})(\\sqrt{6}+\\sqrt{2}+\\sqrt{5})}{(\\sqrt{6}+\\sqrt{2}-\\sqrt{5})(\\sqrt{6}+\\sqrt{2}+\\sqrt{5})}$<\/span><\/p><p><span class=\"math-tex\">$B=\\dfrac{(3+4\\sqrt{3})(\\sqrt{6}+\\sqrt{2}+\\sqrt{5})}{(\\sqrt{6}+\\sqrt{2})^2-(\\sqrt{5})^2}$<\/span><\/p><p><span class=\"math-tex\">$B=\\dfrac{(3+4\\sqrt{3})(\\sqrt{6}+\\sqrt{2}+\\sqrt{5})}{3+4\\sqrt{3}}$<\/span><\/p><p><span style=\"color:#16a085;\"><span class=\"math-tex\">$B=\\sqrt{6}+\\sqrt{2}+\\sqrt{5}$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-07 03:13:49","option_type":"math","len":0},{"id":"7423","post_id":"7795","mon_id":"1159278","chapter_id":"1159327","question":"<p>\u0110i\u1ec1n d\u1ea5u thích h\u1ee3p vào ch\u1ed7 ch\u1ea5m <span style=\"color:#8e44ad;\"><span class=\"math-tex\">$\\dfrac{30-2\\sqrt{45}}{4}$<\/span> ... <span class=\"math-tex\">$\\sqrt{37}$<\/span><\/span>.<\/p>","options":["<strong>A.<\/strong> >","<strong>B.<\/strong> <","<strong>C.<\/strong> ="],"correct":"2","level":"3","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B.<\/strong> <<\/span><\/p><p>Ta có: <span class=\"math-tex\">$\\dfrac{30-2\\sqrt{45}}{4}=\\dfrac{30-6\\sqrt{5}}{4}=\\dfrac{15-3\\sqrt{5}}{2}$<\/span><\/p><p><span class=\"math-tex\">$\\dfrac{15-3\\sqrt{5}}{2}<\\dfrac{15-3\\sqrt{1}}{2}=6=\\sqrt{36}<\\sqrt{37}$<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-07 03:22:41","option_type":"txt","len":0},{"id":"7424","post_id":"7795","mon_id":"1159278","chapter_id":"1159327","question":"<p>Cho <span class=\"math-tex\">$x=-1\\n$<\/span> . Tính giá tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c <span class=\"math-tex\">$P=\\dfrac{1+2x}{1+\\sqrt{1-2x}}+\\dfrac{1-2x}{1-\\sqrt{1-2x}}$<\/span>.<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$P=-1-2\\sqrt{3}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$P=1-2\\sqrt{3}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$P=-1+2\\sqrt{3}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$P=-1-\\sqrt{3}$<\/span>"],"correct":"1","level":"3","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>A.<\/strong> <span class=\"math-tex\">$P=-1-2\\sqrt{3}$<\/span><\/span><\/p><p><span class=\"math-tex\">$P=\\dfrac{1+2x}{1+\\sqrt{1-2x}}+\\dfrac{1-2x}{1-\\sqrt{1-2x}}$<\/span><\/p><p><span class=\"math-tex\">$P=\\dfrac{1+2.(-1)}{1+\\sqrt{1-2.(-1)}}+\\dfrac{1-2.(-1)}{1-\\sqrt{1-2.(-1)}}$<\/span><\/p><p><span class=\"math-tex\">$P=\\dfrac{-1}{1+\\sqrt{3}}+\\dfrac{3}{1-\\sqrt{3}}$<\/span><\/p><p><span class=\"math-tex\">$P=\\dfrac{-1+\\sqrt{3}}{(1+\\sqrt{3})(1-\\sqrt{3})}+\\dfrac{3+3\\sqrt{3}}{(1+\\sqrt{3})(1-\\sqrt{3})}$<\/span><\/p><p><span class=\"math-tex\">$P=\\dfrac{2+4\\sqrt{3}}{-2}=-1-2\\sqrt{3}$<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-07 03:25:44","option_type":"math","len":0}]}