Đáp án + giải thích các bước giải:
`(74/27<=x<=10/3)`
`\sqrt{4-3\sqrt{10-3x}}=x-2`
`->4-3\sqrt{10-3x}=x^2-4x+4`
`->x^2-4x=-3\sqrt{10-3x}`
`->[x(x-4)]^2=9(10-3x)`
`->x^2(x^2-8x+16)=90-27x`
`->x^4-8x^3+16x^2+27x-90=0`
`->x^4-3x^3-5x^3+15x^2+x^2-3x+30x-90=0`
`->x^3(x-3)-5x^2(x-3)+x(x-3)+30(x-3)=0`
`->(x^3-5x^2+x+30)(x-3)=0`
`->(x^3+2x^2-7x^2-14x+15x+30)(x-3)=0`
`->[x^2(x+2)-7x(x+2)+15(x+2)](x-3)=0`
`->(x^2-7x+15)(x+2)(x-3)=0`
`->(x^2-2.x. 7/2+49/4+11/4)(x+2)(x-3)=0`
`->[(x-7/2)^2+11/4](x+2)(x-3)=0`
`->`\(\left[ \begin{array}{l}x+2=0\\x-3=0\end{array} \right.\)
`->`\(\left[ \begin{array}{l}x=-2(KTM)\\x=3(TM)\end{array} \right.\)
Vậy `S={3}`
