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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 9: giải pt 1. 2 √x-5=1 2. √x-5=3 3. √x ²-6x+9 4. √x ²-8+16=x+2

Toán Lớp 9: giải pt
1. 2 √x-5=1
2. √x-5=3
3. √x ²-6x+9
4. √x ²-8+16=x+2

Comments ( 1 )

  1. 1. 2\sqrt{x}-5=1
    ->2\sqrt{x}=6
    ->\sqrt{x}=3
    ->x=9
    2. \sqrt{x}-5=3
    ->\sqrt{x}=8
    ->x=64
    3. \sqrt{x^{2}-6x+9}
    =\sqrt{(x-3)^{2}}
    =|x-3|
    TH1:xge3
    ->x-3
    TH2:xle3
    ->3-x
    4. \sqrt{x^{2}-8x+16}=x+2
    ->\sqrt{(x-4)^{2}}=x+2
    ->|x-4|=x+2
    TH1:xge4
    ->x-4=x+2
    ->0x=6(KTM)
    TH2:xle4
    ->4-x=x+2
    ->-2x=-2
    ->x=1
    Vậy S={1}
     

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222-9+11+12:2*14+14 = ? ( )