Question

Giải các bất phương trình sau :

a) 2x+3/7 > x-5/4

b) 2x+3/4 > 5x-3/2 + 1

c) 2(-2x + 1) > -x + 3

Answer 1

\(2x+\dfrac{3}{7}>x-\dfrac{5}{4}\)

\(\Leftrightarrow2x-x>\dfrac{-5}{4}-\dfrac{3}{7}\)

\(\Rightarrow x>\dfrac{-47}{28}\)

Answer 2

\(2x+\dfrac{3}{4}>5x-\dfrac{3}{2}+1\)

\(\Leftrightarrow2x+\dfrac{3}{2}>5x-\dfrac{1}{2}\)

\(\Leftrightarrow2x-5x>\dfrac{-1}{2}-\dfrac{3}{4}\)

\(\Leftrightarrow-3x>\dfrac{-5}{4}\)

\(\Leftrightarrow3x< \dfrac{5}{4}\)

\(\Rightarrow x< \dfrac{5}{12}\)