{"common":{"save":0,"post_id":"7754","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"7216","post_id":"7754","mon_id":"1159278","chapter_id":"1159281","question":"<p>C\u1eb7p s\u1ed1 (–4 ; 5) là nghi\u1ec7m c\u1ee7a h\u1ec7 ph\u01b0\u01a1ng trình nào sau \u0111ây?<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$\\begin{cases}2x+y=-3\\\\-3x+2y=21\\end{cases}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$\\begin{cases}x-4y=-24\\\\3x+y=-7\\end{cases}$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$\\begin{cases}x-4y=24\\\\3x+y=-7\\end{cases}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$\\begin{cases}2x+y=-3\\\\-3x+2y=-21\\end{cases}$<\/span>"],"correct":"2","level":"2","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B.<\/strong> <span class=\"math-tex\">$\\begin{cases}x-4y=-24\\\\3x+y=-7\\end{cases}$<\/span>.<\/span><\/p><p>Thay x = –4 và y = 5 vào <span class=\"math-tex\">$\\begin{cases}x-4y=-24\\\\3x+y=-7\\end{cases}$<\/span> \u0111\u01b0\u1ee3c <span class=\"math-tex\">$\\begin{cases}-4-4.5=-24\\\\3.(-4)+5=-7\\end{cases}$<\/span> (\u0111úng).<\/p><p>Nên <span class=\"math-tex\">$(-4;5)$<\/span> là nghi\u1ec7m c\u1ee7a h\u1ec7 ph\u01b0\u01a1ng trình <span class=\"math-tex\">$\\begin{cases}x-4y=-24\\\\3x+y=-7\\end{cases}$<\/span>.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-04 02:09:32","option_type":"math","len":0},{"id":"7219","post_id":"7754","mon_id":"1159278","chapter_id":"1159281","question":"<p>Gi\u1ea3i h\u1ec7 ph\u01b0\u01a1ng trình: <span class=\"math-tex\">$\\begin{cases}2x-11y=-7\\\\10x+11y=31\\end{cases}$<\/span>.<\/p>","options":["<strong>A.<\/strong> (–1 ; 2)","<strong>B.<\/strong> (–2 ; 1)","<strong>C.<\/strong> (1 ; 2)","<strong>D.<\/strong> (2 ; 1)"],"correct":"4","level":"2","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>D.<\/strong> (2 ; 1).<\/span><\/p><p>C\u1ed9ng t\u1eebng v\u1ebf c\u1ee7a hai ph\u01b0\u01a1ng trình ta \u0111\u01b0\u1ee3c: 12x = 24 hay x = 2.<br \/>Thay x = 2 vào ph\u01b0\u01a1ng trình th\u1ee9 nh\u1ea5t ta \u0111\u01b0\u1ee3c 2.2 – 11.y = –7 hay y = 1.<br \/>V\u1eady (2 ; 1) là nghi\u1ec7m c\u1ee7a h\u1ec7 ph\u01b0\u01a1ng trình.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-04 02:17:49","option_type":"txt","len":2},{"id":"7221","post_id":"7754","mon_id":"1159278","chapter_id":"1159281","question":"<p>Nghi\u1ec7m c\u1ee7a h\u1ec7 ph\u01b0\u01a1ng trình <span class=\"math-tex\">$\\begin{cases}3x+5y=1\\\\2x-y=-8\\end{cases}$<\/span> là<\/p>","options":["<strong>A.<\/strong> (3 ; 2)","<strong>B.<\/strong> (–3 ; 2)","<strong>C.<\/strong> (2 ; 3)","<strong>D.<\/strong> (1 ; 3)"],"correct":"2","level":"2","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B.<\/strong> (–3 ; 2).<\/span><\/p><p>T\u1eeb ph\u01b0\u01a1ng trình hai ta \u0111\u01b0\u1ee3c y = 2x + 8.<\/p><p>Thay vào ph\u01b0\u01a1ng trình th\u1ee9 nh\u1ea5t ta \u0111\u01b0\u1ee3c: 3x + 5(2x + 8) = 1.<br \/>Suy ra 13x = –39 hay x = –3. Khi \u0111ó y = 2.(–3) + 8 = 2.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"127","test":"0","date":"2024-10-04 02:22:26","option_type":"txt","len":2}]}
