Question

[chang]

5. giải phương trình 

a.\(\sqrt{\left(x-3\right)^2}=3-x\)

b.\(\sqrt{4x^2-20x+25}+2x=5\)

c.\(\sqrt{1-12x+36x^2}=5\)

Answer 1

[Nguyễn Lê Phước Thịnh]

a: Ta có: \(\sqrt{\left(x-3\right)^2}=3-x\)

\(\Leftrightarrow\left|x-3\right|=3-x\)

\(\Leftrightarrow x-3\le0\)

hay \(x\le3\)

b: Ta có: \(\sqrt{4x^2-20x+25}+2x=5\)

\(\Leftrightarrow\left|2x-5\right|=5-2x\)

\(\Leftrightarrow2x-5\le0\)

hay \(x\le\dfrac{5}{2}\)