Question

Mn giúp mik với

Answer 1

a: x-2>4x+5

=>4x+5<x-2

=>3x<-7

hay x<-7/3

b: 3x-1<3+2(x+1)

=>3x-1<3+2x+2

=>3x-1<2x+5

=>x<6

c: 3x+4>2x+3

=>3x-2x>3-4

=>x>-1

d: 4x-8>=3(3x-1)

=>4x-8>=9x-3

=>-5x>=5

hay x<=-1

Answer 2

\(a,x-2>4x+5\)

\(\Leftrightarrow x-2-4x-5>0\)

\(\Leftrightarrow-3x-7>0\)

\(\Leftrightarrow-3x>7\)

\(\Leftrightarrow x< -\dfrac{7}{3}\)(Chia số âm,BPT đổi dấu)

\(b,3x-1< 3+2\left(x+1\right)\)

\(\Leftrightarrow3x-1-3-2x-2< 0\)

\(\Leftrightarrow x-6< 0\)

\(\Leftrightarrow x< 6\)

\(c,3x+4>2x+3\)

\(\Leftrightarrow3x+4-2x-3>0\)

\(\Leftrightarrow x+1>0\)

\(\Leftrightarrow x>-1\)

\(d,4x-8\ge3\left(3x-1\right)\)

\(\Leftrightarrow4x-8-9x+3\ge0\)

\(\Leftrightarrow-5x-5\ge0\)

\(\Leftrightarrow-5x\ge5\)

\(\Leftrightarrow x\le-1\) (Chia số âm,BPT đổi dấu)