giúp mik vs ạ mik đag cần gấp pls
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Câu 5:
a. $|x+\frac{4}{5}|-\frac{1}{7}=0$
$|x+\frac{4}{5}|=\frac{1}{7}$
$\Rightarrow x+\frac{4}{5}=\pm \frac{1}{7}$
$\Rightarrow x=\frac{-23}{35}$ hoặc $x=\frac{-33}{35}$
v.
$2x+5-(x-7)=18$
$2x+5-x+7=18$
$x+12=18$
$x=6$
c.
$2(x+1)+4^2=2^4$
$2(x+1)+16=16$
$2(x+1)=0$
$x+1=0$
$x=-1$
d.
$\frac{x-3}{x+5}=\frac{5}{7}$
$\Rightarrow 7(x-3)=5(x+5)$
$\Rightarrow 7x-21=5x+25$
$\Rightarrow 2x=46$
$\Rightarrow x=23$
Câu 5:
\(a,\left|x+\dfrac{4}{5}\right|-\dfrac{1}{7}=0\\ \Leftrightarrow\left|x+\dfrac{4}{5}\right|=\dfrac{1}{7}\\ \Leftrightarrow\left[{}\begin{matrix}x+\dfrac{4}{5}=\dfrac{1}{7}\\x+\dfrac{4}{5}=-\dfrac{1}{7}\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{7}-\dfrac{4}{5}\\x=-\dfrac{1}{7}-\dfrac{4}{5}\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{23}{35}\\x=-\dfrac{33}{35}\end{matrix}\right.\\ b,2x+5-\left(x-7\right)=18\\ \Leftrightarrow2x-x=18-5-7\\ \Leftrightarrow x=6\\ c,2\left(x+1\right)+4^2=2^4\\ \Leftrightarrow2\left(x+1\right)=2^4-4^2=16-16\\ \Leftrightarrow2\left(x+1\right)=0\\ \Rightarrow x+1=0\\ \Leftrightarrow x=0-1=-1\\ d,\dfrac{x-3}{x+5}=\dfrac{5}{7}\left(x\ne-5\right)\\ \Leftrightarrow7\left(x-3\right)=5\left(x+5\right)\\ \Leftrightarrow7x-21=5x+25\\ \Leftrightarrow7x-5x=25+21\\ \Leftrightarrow2x=46\\ \Leftrightarrow x=23\)
1. Yes,it is.
2. They watch TV about 5 hours (35(hours Americans watch TV for a week):7)
3. Because they think that there is a lot of violence on TV today, the programs are terrible and people don't get any exercise because they only sit and watch TV.
4. It brings news from around the world.
5. We learn many useful things.
\(\left(x-1\right)^2=5^2\\\Rightarrow x-1=5\\ \Rightarrow x=5+1=6\)
20:
1: Xét ΔACD và ΔABE có
AC=AB
góc A chung
AD=AE
=>ΔACD=ΔABE
2: ΔABE=ΔACD
=>góc ABE=góc ACD
=>góc IBD=góc ICE
3: Xét ΔIBD và ΔICE có
góc IBD=góc ICE
BD=CE
góc IDB=góc IEC
=>ΔIBD=ΔICE
4: ΔIBD=ΔICE
=>IB=IC; ID=IE
=>ΔIBC cân tại I; ΔIDE cân tại I
milk c.ơn bn 😀