Giúp tớ với các cậu ơi:
Tìm x, biết:
\(\dfrac{x+3}{-4}=\dfrac{-9}{x+3}\)
K
Khách
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H
6 tháng 2
-5/14 - 2/14 + 1/8 + 1/8=-1/4
-5/22 - 1 + 3/2 - 6/22=0
-1/2 + 1/4 + 2/8 - 11/77=-1/7
2/5 + 5/4 + (-2/5+5/4)-5/2=0
mình trả lời thế có đúng không nhỉ? 🤔
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
6 tháng 2
- \(\dfrac{5}{14}\) - \(\dfrac{2}{14}\) + \(\dfrac{1}{8}\) + \(\dfrac{1}{8}\)
= -(\(\dfrac{5}{14}\) + \(\dfrac{2}{14}\)) + (\(\dfrac{1}{8}\) + \(\dfrac{1}{8}\))
= - \(\dfrac{7}{14}\) + \(\dfrac{2}{8}\)
= - \(\dfrac{1}{2}\) + \(\dfrac{1}{4}\)
= - \(\dfrac{1}{4}\)
6 tháng 2
Bài 1:
a)
\(\dfrac{1}{-5}=\dfrac{1:-1}{-5:-1}=\dfrac{-1}{5}\)
\(\dfrac{-3}{-15}=\dfrac{-3:-3}{-15:-3}=\dfrac{1}{5}\)
Vì \(-1< 1\) nên\(\dfrac{-1}{5}< \dfrac{1}{5}\)
Vậy \(\dfrac{1}{-5}< \dfrac{-3}{-15}\)
b)
\(\dfrac{25}{-10}=\dfrac{25:-5}{-10:-5}=\dfrac{-5}{2}\)
\(\dfrac{15}{-2}=\dfrac{15:-1}{-2:-1}=\dfrac{-15}{2}\)
Vì \(-5>-15\) nên\(\dfrac{-5}{2}>\dfrac{-15}{2}\)
Vậy \(\dfrac{25}{-10}>\dfrac{15}{-2}\)
Bài 2:
a)
\(\dfrac{300}{540}=\dfrac{300:60}{540:60}=\dfrac{5}{9}\)
b)
\(\dfrac{-38}{95}=\dfrac{-38:19}{95:19}=\dfrac{-2}{5}\)
c)
\(\dfrac{-68}{-85}=\dfrac{-68:-17}{-85:-17}=\dfrac{4}{5}\)
Bài 3:
a)
\(\dfrac{x}{3}=-\dfrac{4}{6}\)
\(\dfrac{x}{6}=-\dfrac{4}{6}\)
\(x=-4\)
b) \(x-\dfrac{1}{3}=\dfrac{8}{6}\)
\(x=\dfrac{8}{6}+\dfrac{1}{3}\)
\(x=\dfrac{5}{3}\)
c) \(\dfrac{x}{9}=\dfrac{4}{x}\)
\(x^2=36\)
\(x=6\)
d) mình có giải câu hỏi trước rồi nhé
6 tháng 2
Sửa câu c)
\(x^2=36\)
\(\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)
D
datcoder
Giáo viên
6 tháng 2
ĐKXĐ: \(\left\{{}\begin{matrix}x-5\ne0\\x+2\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ne5\\x\ne-2\end{matrix}\right.\)
\(\dfrac{3}{x-5}=\dfrac{-4}{x+2}\\ \Leftrightarrow3\left(x+2\right)=-4\left(x-5\right)\\ \Leftrightarrow3x+6=-4x+20\\ \Leftrightarrow7x=14\\ \Leftrightarrow x=2\left(tm\right)\)
Vậy x = 2
SV
Sinh Viên NEU
CTVVIP
6 tháng 2
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3.What/Which color do you like?
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6.How long/How often does this film last?
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8.Why/What don't you like watching horror films?
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SV
Sinh Viên NEU
CTVVIP
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How much time do you spend watching movies every weekend?
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H
4
ĐKXĐ: \(x+3\ne0\Leftrightarrow x\ne-3\)
\(\dfrac{x+3}{-4}=\dfrac{-9}{x+3}\\ \Leftrightarrow\left(x+3\right)\left(x+3\right)=\left(-9\right).\left(-4\right)\\ \Leftrightarrow\left(x+3\right)^2=6^2\\ \Rightarrow\left[{}\begin{matrix}x+3=6\\x+3=-6\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=3\left(tm\right)\\x=-9\left(tm\right)\end{matrix}\right.\)
Vậy ...
\(\dfrac{x+3}{-4}=\dfrac{-9}{x+3}\)
\(\left(x+3\right)\left(x+3\right)=\left(-9\right)\cdot\left(-4\right)\)
\(\left(x+3\right)^2=36\)
\(\left(x+3\right)^2=6^2\)
\(x+3=6\)
\(x=3\)