Đáp án+Giải thích các bước giải:
`a+b+c=2\sqrt{a-2}+4\sqrt{b-3}+2\sqrt{c-1}(a>=2;b>=3;c>=1)`
`<=>a-2\sqrt{a-2}+b-4\sqrt{b-3}+c-2\sqrt{c-1}=0`
`<=>a-2-2\sqrt{a-2}+1+b-3-4\sqrt{b-3}+4+c-1-2\sqrt{c-1}+1=0`
`<=>(\sqrt{a-2}-1)^2+(\sqrt{b-3}-2)^2+(\sqrt{c-1}-1)^2=0`
`<=>{((\sqrt{a-2}-1)^2=0),((\sqrt{b-3}-2)^2=0),((\sqrt{c-1}-1)^2=0):}`
`<=>{(\sqrt{a-2}=1),(\sqrt{b-3}=2),(\sqrt{c-1}=1):}`
`<=>{(a-2=1),(b-3=4),(c-1=1):}`
`<=>{(a=3),(b=7),(c=2):}`(tm)
`=>Q=3a+7b-2c`
`=3.3+7.7-2.2`
`=9+49-4`
`=54`
