Tìm kiếm
Nguyễn Tươi
2 tháng trước

Giải phương trình :

3(x-2)-x*2+4=0

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Doraemon50th
2 tháng trước

Giải thích các bước giải:

3(x-2)-x2+4=0

⇔3x-6-x2+4=0

⇔-x2+3x-2=0

⇔-x2+2x+x-2=0

⇔-x(x-2)+(x-2)=0

⇔(1-x)(x-2)=0

⇔1-x=0  hoặc  x-2=0

+)1-x=0⇔x=1

+)x-2=0⇔x=2

Vậy phương trình trên có tập nghiệm S={1;2}

ohnonono
2 tháng trước

3(x-2)-x2+4=0

⇔3x-6-x2+4=0

⇔-x2+3x-2=0

⇔-x2+2x+x-2=0

⇔-x(x-2)+(x-2)=0

⇔(1-x)(x-2)=0

⇔[1-x=0x-2=0

⇔[x=1x=2

Vậy S={1;2}

 

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Air pollution is a cause of ill-health in (31) ________ . In many countries there are laws limiting the amount of smoke that factories can produce. Although there isn’t (32) ________ on the (33) ________ of smoke in the atmosphere, doctors have proved that air pollution causes lung diseases. The gases from the exhausts of cars have also (34) ________ air pollution in (35) ________ cities. The (36) ________ in petrol produces a poisonous gas that often collects in busy street surrounded by high buildings. Children (37) ________ live in areas where there is a lot of lead in the atmosphere cannot think as (38) ________ as other children and are clumsy when they use their hands. There are other long-term effects of pollution. If the gases in the atmosphere continue (39) ________ increase, the earths climate may become warmer. A lot of the ice near the Poles may (40) ________ and may cause serious floods. 36. A. lead B. zinc C. bronze D. steel 37. A. who B. which C. those D. whom 38. A. quick B. quickly C. fastly D. intelligent 39. A. along B. down C. toward D. to 40. A. melt B. freeze C. defrost D. flow

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1 đáp án
3 giờ trước

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