Question

[nguyễn thị thanh]

Giải các pt sau:\(\sqrt{x^2-2x+1}+\sqrt{x^2-4x+4}=3\)

\(\sqrt{x^2-10x+25}=3-19x\)

\(\sqrt{2x-2+2\sqrt{2x-3}}+\sqrt{2x+13+8\sqrt{2x-3}}=5\)

Answer 1

[Đặng Thị Hà Tiên]

\(\sqrt{x^2-2x+1}\) + \(\sqrt{x^2-4x+4}\) = 3

<=> \(\sqrt{\left(x-1\right)^2}\)+ \(\sqrt{\left(x-2\right)^2}\)= 3

<=> \(\left|x-1\right|\)+\(\left|x-2\right|\)=3

<=> x - 1 + x - 2 = 3

<=> 2x - 3 = 3

<=> x = \(\dfrac{6}{2}\)= 3

b ,

\(\sqrt{x^2-10x+25}=3-19x\)

<=>\(\sqrt{\left(x-5\right)^2}=3-19x\)

<=> \(\left|x-5\right|=3-19x\)

<=> \(x-5=3-19x\)

\(\Leftrightarrow x+19x=3+5\)

\(\Leftrightarrow20x=8\Leftrightarrow x=\dfrac{8}{20}=\dfrac{2}{5}\)