Question

Tìm x:a)/2x-5/+5=2x

            b)/7x+3/=66-x

            c)/5x-2/≤2

Nhanh hộ mình

Answer 1

a) \(\left|2x-5\right|+5=2x\)

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

\(\Rightarrow2x-5>0\Rightarrow x\ge2,5\)

Vậy \(x\inℝ;x\ge2,5\)

b) \(\left|7x+3\right|=66-x\)

Khi \(\left|7x+3\right|=7x+3\)thì \(x\ge\frac{-3}{7}\)

\(\Rightarrow7x+3=66-x\)

      \(7x+x=66-3\)

               \(8x=63\)

                 \(x=\frac{63}{8}\)

Vậy \(x=\frac{63}{8}\)

c) \(\left|5x-2\right|\le2\)

Khi \(\left|5x-2\right|=2\Rightarrow\orbr{\begin{cases}x=0\\x=0,8\end{cases}}\)

Khi \(\left|5x-2\right|=1\Rightarrow\orbr{\begin{cases}x=0,6\\x=0,2\end{cases}}\)

Khi \(\left|5x-2\right|=0\Rightarrow x=0,4\)

Vậy \(x\in\left\{0;0,8;0,6;0,2;0,4\right\}\)