căn(1-x)=2x-2 giupssssssssssss

1 bình luận về “căn(1-x)=2x-2 giupssssssssssss”

1. Giải đáp:

   \sqrt{1-x}=2x-2 (đk: 1-x\ge0=> -x\ge-1 => x\le1;2x-2\ge0=> 2x\ge2=> x\ge1)

   <=> (\sqrt{1-x})^{2}=(2x-2)^{2}

   <=> 1-x=2^{2}.(x-1)^{2}

   <=> 1-x=4.(x^{2}-2x+1)

   <=> 1-x=4x^{2}-8x+4

   <=> 1-x-4x^{2}+8x-4=0

   <=> -4x^{2}+7x-3=0

   <=> -(4x^{2}-7x+3)=0

   <=> -(4x^{2}-4x-3x+3)=0

   <=> 4x.(x-1)-3.(x-1)=0

   <=> (4x-3).(x-1)=0

   <=> \(\left[ \begin{array}{l}4x-3=0\\x-1=0\end{array} \right.\)

   <=>\(\left[ \begin{array}{l}4x=3\\x=1(tmđk)\end{array} \right.\)

   <=> x=\frac{3}{4}(ktmđk) và x=1(tmđk)

   Vậy S={1}

   #DYNA

    

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