Question

 giúp em câu 7,8,9

Answer 1

giúp em câu 7,8,9 bài 6

 

Answer 2

\(7,\\ 1,ĐK:-3x\ge0\Leftrightarrow x\le0\\ 2,ĐK:4-2x\ge0\Leftrightarrow x\le-2\\ 3,ĐK:-3x+2\ge0\Leftrightarrow x\le\dfrac{2}{3}\\ 4,ĐK:\dfrac{4}{2x+3}\ge0\Leftrightarrow2x+3>0\left(2x+3\ne0;4>0\right)\Leftrightarrow x>-\dfrac{3}{2}\\ 5,ĐK:\dfrac{-2}{x+1}\ge0\Leftrightarrow x+1< 0\left(x+1\ne0;-2< 0\right)\Leftrightarrow x< -1\)

Answer 3

Bài 8:

1: Ta có: \(\sqrt{25x}=20\)

\(\Leftrightarrow25x=400\)

hay x=16

2: Ta có: \(2\sqrt{x+1}=6\)

\(\Leftrightarrow x+1=9\)

hay x=8