Question

Bài 2 Tìm x :  a) -1/2.3x+3/4=-2,25

                      b)13-3.|x-2|=10

Answer 1

a) \(\frac{-1}{2}.3x+\frac{3}{4}=-2,25\)

\(\frac{-1}{2}.3x+\frac{3}{4}=\frac{9}{4}\)

\(\frac{-1}{2}.3x=\frac{9}{4}-\frac{3}{4}\)

\(\frac{-1}{2}.3x=\frac{6}{4}=\frac{3}{2}\)

\(3x=\frac{3}{2}:\frac{-1}{2}\)

\(3x=-3\)

\(x=\left(-3\right):3\)

\(x=-1\)

b) \(13-3\left|x-2\right|=10\)

\(3\left|x-2\right|=13-10\)

\(3\left|x-2\right|=3\)

\(\left|x-2\right|=3:3\)

\(\left|x-2\right|=1\)

\(\Rightarrow\hept{\begin{cases}\left|x-2\right|=1\\\left|x-2\right|=-1\end{cases}\Rightarrow\hept{\begin{cases}x=3\\x=1\end{cases}}}\)