Question

Giải các phương trình

a)\(\dfrac{15}{4}-2,5:\left|\dfrac{3}{4}x+\dfrac{1}{2}\right|=3\)

b) \(6,5-\dfrac{9}{4}:\left|x+\dfrac{1}{3}\right|=2\)

c) \(\left|\dfrac{5}{4}x-\dfrac{7}{2}\right|-\left|\dfrac{5}{8}x+\dfrac{3}{5}\right|=0\)

Answer 1

a: \(\Leftrightarrow\dfrac{5}{2}:\left|\dfrac{3}{4}x+\dfrac{1}{2}\right|=\dfrac{15}{4}-3=\dfrac{3}{4}\)

\(\Leftrightarrow\left|\dfrac{3}{4}x+\dfrac{1}{2}\right|=\dfrac{5}{2}:\dfrac{3}{4}=\dfrac{5}{2}\cdot\dfrac{4}{3}=\dfrac{20}{6}=\dfrac{10}{3}\)

=>3/4x+1/2=10/3 hoặc 3/4x+1/2=-10/3

=>3/4x=17/6 hoặc 3/4x=-23/6

=>x=34/9 hoặc x=-46/9

b: \(\Leftrightarrow\dfrac{9}{4}:\left|x+\dfrac{1}{3}\right|=6.5-2=\dfrac{9}{2}\)

\(\Leftrightarrow\left|x+\dfrac{1}{3}\right|=\dfrac{9}{4}:\dfrac{9}{2}=\dfrac{1}{2}\)

=>x+1/3=1/2 hoặc x+1/3=-1/2

=>x=1/6 hoặc x=-5/6