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Home Lớp 10 Toán lớp 10 - Sách Kết nối tri thức Bài 1: Mệnh đềBài tập trung bình

{"common":{"save":0,"post_id":"6066","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"5212","mon_id":"1158767","chapter_id":"1158770","post_id":"6066","question":"M\u1ec7nh \u0111\u1ec1 nào sau \u0111ây là sai?<\/strong><\/p>","options":["A. <\/strong>Ph\u01b0\u01a1ng trình $x^2+bx+c=0$<\/span> có nghi\u1ec7m khi và ch\u1ec9 khi $b^2-4c \\ge 0$<\/span> .","B. <\/strong>$\\begin{cases} a>b \\\\ b>c \\end{cases} \\Leftrightarrow a>c$<\/span>","C.<\/strong> $\\triangle ABC$<\/span> vuông t\u1ea1i A khi và ch\u1ec9 khi $\\widehat{B}+\\widehat{C}=90^0$<\/span> .","D.<\/strong> $x^2 = 0 \\Leftrightarrow x = 0$<\/span>"],"correct":"2","level":"2","hint":"","answer":"Các m\u1ec7nh \u0111\u1ec1 \u1edf các \u0111áp án A, C, D<\/strong> là các m\u1ec7nh \u0111\u1ec1 \u0111úng.<\/p>M\u1ec7nh \u0111\u1ec1 trong câu B. <\/strong>$\\begin{cases} a>b \\\\ b>c \\end{cases} \\Leftrightarrow a>c$<\/span>  là m\u1ed9t m\u1ec7nh \u0111\u1ec1 sai,<\/p>vì \u0111i\u1ec1u ng\u01b0\u1ee3c l\u1ea1i không \u0111úng: $a>c \\Rightarrow \\begin{cases} a>b \\\\ b > c \\end{cases}$<\/span> <\/p>Ch\u1eb3ng h\u1ea1n n\u1ebfu a = 4; b = 1 và c = 2 thì  $4 > 2 \\Rightarrow \\begin{cases} 4>1 \\\\ 1 > 2 \\end{cases}$<\/span>  là m\u1ed9t \u0111i\u1ec1u vô lí (1 > 2 là vô lí).<\/p>\u0110áp án c\u1ea7n ch\u1ecdn là  B. <\/strong>$\\begin{cases} a>b \\\\ b>c \\end{cases} \\Leftrightarrow a>c$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2022-08-29 13:08:40","option_type":"math","len":0},{"id":"5213","mon_id":"1158767","chapter_id":"1158770","post_id":"6066","question":"Ph\u1ee7 \u0111\u1ecbnh c\u1ee7a m\u1ec7nh \u0111\u1ec1<\/p>" $\\forall x \\in \\mathbb{R} , x^2 + 1 > 0$<\/span> " là:<\/p>","options":["A.<\/strong> " $\\forall x \\in \\mathbb{R} , x^2 + 1 \\le 0$<\/span> "","B.<\/strong> " $\\exists x \\in \\mathbb{R} , x^2 \\ge 0$<\/span> "","C.<\/strong> " $\\exists x \\in \\mathbb{R}, x^2 + 1 \\le 0$<\/span> "","D.<\/strong> " $\\forall x \\in \\mathbb{R} , x^2 + 1 \\ge 0$<\/span> ""],"correct":"3","level":"2","hint":"","answer":"Vì  $\\overline{x^2 + 1 > 0}$<\/span>   là  $x^2 + 1 \\le 0$<\/span>  nên <\/p>\u0111áp án \u0111úng là  C.<\/strong> " $\\exists x \\in \\mathbb{R}, x^2 + 1 \\le 0$<\/span> "<\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2022-08-29 13:20:49","option_type":"math","len":0},{"id":"5215","mon_id":"1158767","chapter_id":"1158770","post_id":"6066","question":"Ph\u1ee7 \u0111\u1ecbnh c\u1ee7a m\u1ec7nh \u0111\u1ec1 <\/p>" $\\exists x \\in \\mathbb{R} , x^2 - 5x +4 = 0$<\/span> "  là<\/p>","options":["A.<\/strong> " $\\forall x \\in \\mathbb{R} , x^2 -5x + 4 \\ne 0$<\/span> "","B.<\/strong> " $\\forall x \\in \\mathbb{R} , x^2 -5x + 4 = 0$<\/span> "","C.<\/strong> " $\\forall x \\in \\mathbb{R} , x^2 -5x + 4 < 0$<\/span> "","D.<\/strong> " $\\forall x \\in \\mathbb{R} , x^2 -5x + 4 > 0$<\/span> ""],"correct":"1","level":"2","hint":"","answer":"Vì  $\\overline{x^2 - 5x + 4 = 0}$<\/span>  là  $x^2 - 5x + 4 \\ne 0$<\/span>  nên<\/p>\u0111áp án \u0111úng là  A.<\/strong> " $\\forall x \\in \\mathbb{R} , x^2 -5x + 4 \\ne 0$<\/span> "<\/span><\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2022-08-29 13:26:11","option_type":"math","len":0}]}