Câu 1:
a: =>2x+3=5 hoặc 2x+3=-5
=>2x=2 hoặc 2x=-8
=>x=1 hoặc x=-4
b: \(\Leftrightarrow\left(x+5\right)\left(\dfrac{1}{2016}+\dfrac{1}{2017}-\dfrac{1}{2018}\right)=0\)
=>x+5=0
hay x=-5
\(a,\left(2x+3\right)^2=25\)
\(\Leftrightarrow\left(2x+3\right)^2-25=0\)
\(\Leftrightarrow\left(2x+3+5\right)\left(2x+3-5\right)=0\)
\(\Leftrightarrow\left(2x+8\right)\left(2x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+8=0\\2x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-4\\x=1\end{matrix}\right.\)
Vậy \(S=\left\{-4;1\right\}\)
\(b,\dfrac{x+5}{2016}+\dfrac{x+5}{2017}-\dfrac{x+5}{2018}=0\)
\(\Leftrightarrow\left(x+5\right)\left(\dfrac{1}{2016}+\dfrac{1}{2017}-\dfrac{1}{2018}\right)=0\)
\(\Leftrightarrow x+5=0\)
\(\Leftrightarrow x=-5\)
Vậy \(S=\left\{-5\right\}\)
\(1b,\dfrac{x+5}{2016}+\dfrac{x+5}{2017}-\dfrac{x+5}{2018}=0\)
\(\Leftrightarrow\dfrac{2017.2018\left(x+5\right)+2016.2018\left(x+5\right)-2016.2017\left(x+5\right)}{2016.2017.2018}=0\)
\(\Leftrightarrow4070306x+20351530+4068288x+20341440-4066272x-20331360=0\)
\(\Leftrightarrow4072322x-20361610=0\)
\(\Leftrightarrow4072322x=20361610\)
\(\Leftrightarrow x=5\)
Vậy \(S=\left\{5\right\}\)
\(2,\)
\(3\left(x+1\right)-2\left(x-1\right)>3\)
\(\Leftrightarrow3x+3-2x+2>3\)
\(\Leftrightarrow x+5>3\)
\(\Leftrightarrow x>-2\)
\(5\left(1-x\right)+2\left(x+2\right)>3\)
\(\Leftrightarrow5-5x+2x+4>3\)
\(\Leftrightarrow-3x+9>3\)
\(\Leftrightarrow-3x>-6\)
\(\Leftrightarrow x< 2\) (Chia số âm,\(BPT\) đổi dấu)
giúp mik bài 1 bài 2 nha