{"common":{"save":0,"post_id":"7375","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"7029","post_id":"7375","mon_id":"1159278","chapter_id":"1159281","question":"<p>X&aacute;c \u0111\u1ecbnh c&aacute;c h\u1ec7 s\u1ed1&nbsp;a&nbsp;v&agrave;&nbsp;b&nbsp;bi\u1ebft h\u1ec7 ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$\\begin{cases}2x+by=2\\\\bx+ay=-4\\end{cases}$<\/span> c&oacute; nghi\u1ec7m l&agrave; (x ; y) = (2 ;&nbsp;&ndash;2).<\/p>","options":["<strong>A.<\/strong> a = 1; b = 2","<strong>B.<\/strong> a = 3; b = 1","<strong>C.<\/strong> a = 1; b = 3","<strong>D.<\/strong> a = 2; b = 1"],"correct":"2","level":"3","hint":"","answer":"<p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>B.<\/strong> a = 3; b = 1.<\/span><\/p><p>Thay x = 2; y = &ndash;2 ta \u0111\u01b0\u1ee3c:&nbsp;<span class=\"math-tex\">$\\begin{cases}4-2b=2\\text{ (1)}\\\\2b-2a=-4\\text{ (2)}\\end{cases}$<\/span>.<\/p><p>T\u1eeb ph\u01b0\u01a1ng tr&igrave;nh (1) ta \u0111\u01b0\u1ee3c 2b = 2 suy ra b = 1.<\/p><p>Th\u1ebf v&agrave;o ph\u01b0\u01a1ng tr&igrave;nh (2) c\u1ee7a h\u1ec7 ta \u0111\u01b0\u1ee3c 2 &ndash; 2a = &ndash;4 suy ra a = 3.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-01 01:44:40","option_type":"txt","len":1},{"id":"7030","post_id":"7375","mon_id":"1159278","chapter_id":"1159281","question":"<p>Cho h\u1ec7 ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$\\begin{cases}3x-2y=m\\\\9x-2m^2y=3\\sqrt{3}\\end{cases}$<\/span>. N\u1ebfu m =&nbsp;<span class=\"math-tex\">$\\sqrt{3}$<\/span>&nbsp;th&igrave; t\u1eadp nghi\u1ec7m c\u1ee7a h\u1ec7 l&agrave;<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$S=\\{(0;\\sqrt{2})\\}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$S=\\{(1;\\sqrt{2})\\}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$S=\\{(\\sqrt{2};1)\\}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$S=\\mathbb{R}$<\/span>"],"correct":"4","level":"3","hint":"<p>Thay m =&nbsp;<span class=\"math-tex\">$\\sqrt{3}$<\/span>&nbsp;\u0111\u01b0\u1ee3c&nbsp;<span class=\"math-tex\">$\\begin{cases}3x-2y=\\sqrt{3}\\\\9x-6y=3\\sqrt{3}\\end{cases}$<\/span>&nbsp;suy ra&nbsp;<span class=\"math-tex\">$\\begin{cases}3x-2y=\\sqrt{3}\\\\3x-2y=\\sqrt{3}\\end{cases}$<\/span>.<\/p><p>T\u1eeb ph\u01b0\u01a1ng tr&igrave;nh th\u1ee9 nh\u1ea5t ta c&oacute;&nbsp;<span class=\"math-tex\">$y=\\dfrac{3x-\\sqrt{3}}{2}$<\/span>&nbsp;(1).<\/p><p>Tr\u1eeb t\u1eebng v\u1ebf hai ph\u01b0\u01a1ng tr&igrave;nh c\u1ee7a h\u1ec7 ta \u0111\u01b0\u1ee3c ...<\/p>","answer":"<p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>D.<\/strong>&nbsp;<span class=\"math-tex\">$S=\\mathbb{R}$<\/span>.<\/span><\/p><p>Thay m =&nbsp;<span class=\"math-tex\">$\\sqrt{3}$<\/span>&nbsp;\u0111\u01b0\u1ee3c&nbsp;<span class=\"math-tex\">$\\begin{cases}3x-2y=\\sqrt{3}\\\\9x-6y=3\\sqrt{3}\\end{cases}$<\/span>&nbsp;suy ra&nbsp;<span class=\"math-tex\">$\\begin{cases}3x-2y=\\sqrt{3}\\\\3x-2y=\\sqrt{3}\\end{cases}$<\/span>.<\/p><p>T\u1eeb ph\u01b0\u01a1ng tr&igrave;nh th\u1ee9 nh\u1ea5t ta c&oacute;&nbsp;<span class=\"math-tex\">$y=\\dfrac{3x-\\sqrt{3}}{2}$<\/span>&nbsp;(1).<\/p><p>Tr\u1eeb t\u1eebng v\u1ebf hai ph\u01b0\u01a1ng tr&igrave;nh c\u1ee7a h\u1ec7 ta \u0111\u01b0\u1ee3c 0x + 0y = 0 (2).<br \/>Ta th\u1ea5y m\u1ecdi gi&aacute; tr\u1ecb c\u1ee7a x; y \u0111\u1ec1u th\u1ecfa m&atilde;n (2).<br \/>V\u1edbi gi&aacute; tr\u1ecb t&ugrave;y &yacute; c\u1ee7a x &isin; \u211d, gi&aacute; tr\u1ecb t\u01b0\u01a1ng \u1ee9ng c\u1ee7a y \u0111\u01b0\u1ee3c t&iacute;nh b\u1edfi (1).<\/p><p>V\u1eady h\u1ec7 ph\u01b0\u01a1ng tr&igrave;nh \u0111&atilde; cho c&oacute; nghi\u1ec7m&nbsp;<span class=\"math-tex\">$\\bigg(x;\\dfrac{3x-\\sqrt{3}}{2}\\bigg)$<\/span>&nbsp;v\u1edbi&nbsp;x &isin; \u211d&nbsp;t&ugrave;y &yacute;.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-01 01:52:10","option_type":"math","len":0},{"id":"7032","post_id":"7375","mon_id":"1159278","chapter_id":"1159281","question":"<p>Nghi\u1ec7m c\u1ee7a h\u1ec7 ph\u01b0\u01a1ng tr&igrave;nh&nbsp;<span class=\"math-tex\">$\\begin{cases}2(x+y)+3(x-y)=4\\\\ (x+y)+2(x-y)=5\\end{cases}$<\/span>&nbsp;l&agrave;<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$\\bigg(\\dfrac{1}{2};\\dfrac{13}{2}\\bigg)$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$\\bigg(-\\dfrac{1}{2};-\\dfrac{13}{2}\\bigg)$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$\\bigg(-\\dfrac{1}{2};\\dfrac{13}{2}\\bigg)$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$\\bigg(\\dfrac{1}{2};-\\dfrac{13}{2}\\bigg)$<\/span>"],"correct":"2","level":"3","hint":"<p>T\u1eeb h\u1ec7 ban \u0111\u1ea7u ta c&oacute;&nbsp;<span class=\"math-tex\">$\\begin{cases}2x+2y+3x-3y=4\\\\x+y+2x-2y=5\\end{cases}$<\/span>&nbsp;hay&nbsp;<span class=\"math-tex\">$\\begin{cases}5x-y=4\\\\3x-y=5\\end{cases}$<\/span>.<\/p><p>Tr\u1eeb t\u1eebng v\u1ebf hai ph\u01b0\u01a1ng tr&igrave;nh c\u1ee7a h\u1ec7 \u0111\u01b0\u1ee3c 2x = &ndash;1, suy ra .....<\/p><p>Th\u1ebf&nbsp;&nbsp;<span class=\"math-tex\">$x=-\\dfrac{1}{2}$<\/span>&nbsp;v&agrave;o ph\u01b0\u01a1ng tr&igrave;nh th\u1ee9 hai \u0111\u01b0\u1ee3c ....<\/p>","answer":"<p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>B.<\/strong>&nbsp;<span class=\"math-tex\">$\\bigg(-\\dfrac{1}{2};-\\dfrac{13}{2}\\bigg)$<\/span>.<\/span><\/p><p>T\u1eeb h\u1ec7 ban \u0111\u1ea7u ta c&oacute;&nbsp;<span class=\"math-tex\">$\\begin{cases}2x+2y+3x-3y=4\\\\x+y+2x-2y=5\\end{cases}$<\/span>&nbsp;hay&nbsp;<span class=\"math-tex\">$\\begin{cases}5x-y=4\\\\3x-y=5\\end{cases}$<\/span>.<\/p><p>Tr\u1eeb t\u1eebng v\u1ebf hai ph\u01b0\u01a1ng tr&igrave;nh c\u1ee7a h\u1ec7 \u0111\u01b0\u1ee3c 2x = &ndash;1, suy ra&nbsp;<span class=\"math-tex\">$x=-\\dfrac{1}{2}$<\/span>.<\/p><p>Th\u1ebf&nbsp;&nbsp;<span class=\"math-tex\">$x=-\\dfrac{1}{2}$<\/span>&nbsp;v&agrave;o ph\u01b0\u01a1ng tr&igrave;nh th\u1ee9 hai \u0111\u01b0\u1ee3c&nbsp;<span class=\"math-tex\">$-\\dfrac{3}{2}-y=5$<\/span>, suy ra&nbsp;<span class=\"math-tex\">$y=-\\dfrac{13}{2}$<\/span>.<\/p><p>V\u1eady h\u1ec7 ph\u01b0\u01a1ng tr&igrave;nh \u0111&atilde; cho c&oacute; nghi\u1ec7m&nbsp;<span class=\"math-tex\">$\\bigg(-\\dfrac{1}{2};-\\dfrac{13}{2}\\bigg)$<\/span>.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-01 02:11:45","option_type":"math","len":0}]}