Giai phuong trinh :\(\frac{x-3}{11}+\frac{x+1}{3}=\frac{x+7}{9}-1\)
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PV
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CT
26 tháng 1 2019
mik ví dụ 1 biểu thức nha
a(a+b+c)+bc/b+c=a^2+ab+ac+bc/b+c=(a+c)(a+b)/b+c
tương tự với mấy biểu thức còn lại
PV
2
26 tháng 1 2019
\(x^2-12+\frac{36}{x^2}-4x+\frac{24}{x}=5\)
\(\Leftrightarrow x^2+\frac{36}{x^2}-4x+\frac{24}{x}=5+12\)
\(\Leftrightarrow x^2+\frac{36}{x^2}-4x+\frac{24}{x}=17\)
\(\Leftrightarrow x^2.x^2+\frac{36}{x^2}.x^2-4x.x^2+\frac{24}{x}.x^2=17x^2\)
\(\Leftrightarrow x^4+36-4x^3+24x=17x^2\)
\(\Leftrightarrow x^4+36-4x^3+24x=17x^2-17x^2\)
\(\Leftrightarrow x^4+36-4x^3+24x=0\)
\(\Leftrightarrow\left(x+1\right)\left(x-2\right)\left(x+3\right)\left(x-4\right)=0\)
\(\Rightarrow x\in\left\{-1;2;-3;4\right\}\)
31 tháng 1 2019
1. We stayed home because the weather was cold
2. Because most people ..., they begin to jog.
3. People ... country because the climate is healthy.
4. Because a ... purposes, it becomes ...
5. Because she was ill, Stacy...
6. We were ... meeting because the traffic was heavy.
7. Harry ... hospital because his leg was broken.
8. Because our ... meeting, it was cancelled.
25 tháng 1 2019
1. A. happy B. apple C. act D. aunt
2. A. mind B. bike C. fit D. tidy
3. A. school B. chair C. church D. chat
4. A. health B. team C. tea D. sea
5. A. sun B. fun C. son D. put
6. A. excited B. interested C. worried D. painted
7. A. use B. computer C. duty D. shut
8. A. chair B. fair C. pair D. are
9. A. how B. know C. town D. brown
10. A. season B. break C. great D. steak
\(\frac{x-3}{11}+\frac{x+1}{3}=\frac{x+7}{9}-1\)
\(\Leftrightarrow\frac{9\left(x-3\right)}{99}+\frac{33\left(x+1\right)}{99}=\frac{11\left(x+7\right)}{99}-\frac{99}{99}\)
\(\Leftrightarrow\frac{9\left(x-3\right)+33\left(x+1\right)}{99}=\frac{11\left(x+7\right)-99}{99}\)
\(\Leftrightarrow9\left(x-3\right)+33\left(x+1\right)=11\left(x+7\right)-99\)
\(\Leftrightarrow9x-27+33x+33=11x+77-99\)
\(\Leftrightarrow42x+6=11x-22\Leftrightarrow42x-11x=-6-22\)
\(\Leftrightarrow31x=-28\Leftrightarrow x=-\frac{28}{31}\)
Vậy phương trình có tập nghiệm S={-28/31}