{"common":{"save":0,"post_id":"6533","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"5745","post_id":"6533","mon_id":"1158921","chapter_id":"1158927","question":"<p>Cho hai \u0111a th\u1ee9c&nbsp;<span class=\"math-tex\">$C=y^2-2xyz+z^3$<\/span>&nbsp;v&agrave;&nbsp;<span class=\"math-tex\">$D=-y^2+3xyz-z^3+3$<\/span>. T&igrave;m b\u1eadc c\u1ee7a \u0111a th\u1ee9c&nbsp;<span class=\"math-tex\">$-C-D$<\/span>.<\/p>","options":["<b>A. <\/b>2","<b>B. <\/b>3","<b>C. <\/b>1","<b>D. <\/b>5"],"correct":"2","level":"2","hint":"","answer":"<p>&nbsp; &nbsp; &nbsp; &nbsp;<span class=\"math-tex\">$-C=-y^2+2xyz-z^3$<\/span><\/p><p>&nbsp; &nbsp; &nbsp; &nbsp;<span class=\"math-tex\">$-D=y^2-3xyz+z^3-3$<\/span><\/p><p><span class=\"math-tex\">$-C-D$<\/span>&nbsp;<span class=\"math-tex\">$=-y^2+y^2+2xyz-3xyz-z^3+z^3-3$<\/span><\/p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">$=-xyz-3$<\/span><\/p><p>H\u1ea1ng t\u1eed&nbsp;<span class=\"math-tex\">$-xyz$<\/span>&nbsp;c&oacute; b\u1eadc 3, h\u1ea1ng t\u1eed&nbsp;<span class=\"math-tex\">$-3$<\/span>&nbsp;c&oacute; b\u1eadc 0. V\u1eady b\u1eadc c\u1ee7a \u0111a th\u1ee9c l&agrave; <span style=\"color:#16a085;\"><strong>3<\/strong><\/span>.<\/p><p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><b>B.&nbsp;<\/b>3<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"0","date":"2023-07-02 02:21:44","option_type":"txt","len":0},{"id":"5746","post_id":"6533","mon_id":"1158921","chapter_id":"1158927","question":"<p>Cho hai \u0111a th\u1ee9c&nbsp;<span class=\"math-tex\">$C=y^2-2xyz+z^3$<\/span>&nbsp;v&agrave;&nbsp;<span class=\"math-tex\">$D=-y^2+3xyz-z^3+3$<\/span>. T&iacute;nh gi&aacute; tr\u1ecb&nbsp;c\u1ee7a \u0111a th\u1ee9c&nbsp;<span class=\"math-tex\">$C+D$<\/span>&nbsp;t\u1ea1i <span class=\"math-tex\">$x=\\dfrac{1}{5},y=10,z=-3$<\/span>.<\/p>","options":["<b>A. <\/b>&ndash;9","<b>B. <\/b>9","<b>C. <\/b>3","<b>D. <\/b>&ndash;3"],"correct":"4","level":"2","hint":"","answer":"<p>&nbsp; &nbsp; &nbsp; &nbsp;<span class=\"math-tex\">$C=y^2-2xyz+z^3$<\/span><\/p><p>&nbsp; &nbsp; &nbsp; &nbsp;<span class=\"math-tex\">$D=-y^2+3xyz-z^3+3$<\/span><\/p><p><span class=\"math-tex\">$C+D$<\/span>&nbsp;<span class=\"math-tex\">$=y^2-y^2-2xyz+3xyz+z^3-z^3+3$<\/span><\/p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<span class=\"math-tex\">$=xyz+3$<\/span><\/p><p>T\u1ea1i&nbsp;<span class=\"math-tex\">$x=\\dfrac{1}{5},y=10,z=-3$<\/span>&nbsp;ta \u0111\u01b0\u1ee3c&nbsp;<span class=\"math-tex\">$\\dfrac{1}{5}.10.(-3)+3=-3$<\/span><\/p><p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><b>D.&nbsp;<\/b>&ndash;3<\/span><\/p>","type":"choose","extra_type":"shape1","time":"0","user_id":"131","test":"0","date":"2023-07-02 02:22:07","option_type":"txt","len":0},{"id":"5749","post_id":"6533","mon_id":"1158921","chapter_id":"1158927","question":"<p>Thu g\u1ecdn \u0111a th\u1ee9c&nbsp;<span class=\"math-tex\">$X=(\\dfrac{1}{2}x^4-3x^2y+2xy-x^2)+(2x^2y-2xy^2+3xy+2x^2)$<\/span>.<\/p>","options":["<strong>A. <\/strong><span class=\"math-tex\">$\\dfrac{1}{2}x^4-x^2y-2xy^2+5xy+x^2$<\/span>","<strong>B. <\/strong><span class=\"math-tex\">$-\\dfrac{1}{2}x^4+x^2y+2xy^2-5xy-x^2$<\/span>","<strong>C. <\/strong><span class=\"math-tex\">$\\dfrac{1}{2}x^4-x^2y-3xy^2+xy+x^2$<\/span>","<strong>D. <\/strong><span class=\"math-tex\">$-\\dfrac{1}{2}x^4-2x^2y-2xy^2+xy-x^2$<\/span>"],"correct":"1","level":"2","hint":"","answer":"<p><span class=\"math-tex\">$X=(\\dfrac{1}{2}x^4-3x^2y+2xy-x^2)+(2x^2y-2xy^2+3xy+2x^2)$<\/span><\/p><p>&nbsp; &nbsp;&nbsp;<span class=\"math-tex\">$=\\dfrac{1}{2}x^4-3x^2y+2xy-x^2+2x^2y-2xy^2+3xy+2x^2$<\/span><\/p><p>&nbsp; &nbsp;&nbsp;<span class=\"math-tex\">$=\\dfrac{1}{2}x^4-3x^2y+2x^2y-2xy^2+2xy+3xy+2x^2-x^2$<\/span><\/p><p>&nbsp; &nbsp;&nbsp;<span class=\"math-tex\">$=\\dfrac{1}{2}x^4-x^2y-2xy^2+5xy+x^2$<\/span><\/p><p>Ch\u1ecdn&nbsp;<span style=\"color:#16a085;\"><strong>A.&nbsp;<\/strong><span class=\"math-tex\">$\\dfrac{1}{2}x^4-x^2y-2xy^2+5xy+x^2$<\/span><\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"131","test":"0","date":"2023-07-02 02:35:09","option_type":"math","len":0}]}