a: \(=\dfrac{37}{25}\cdot\dfrac{25}{74}\cdot\dfrac{4}{5}=\dfrac{1}{2}\cdot\dfrac{4}{5}=\dfrac{2}{5}\)

b: \(=\dfrac{6}{11}\cdot\dfrac{11}{5}:\dfrac{16}{9}=\dfrac{6}{5}\cdot\dfrac{9}{16}=\dfrac{54}{80}=\dfrac{27}{40}\)

a)=384:(25*4)=384:100=3,84.

b)37/25:5/4:74/25=37/25*4/5*25/74=37*4*25/5*25*74=2/5.

c)380:(38*2)=(380:38):2=10:2=5.

d)6/11:4/3:5/11:4/3=6/11*3/4*11/5*3/4=6*3*11*3/11*4*5*4=27/40.

k nha

a,384:25:4

=15.36:4

=3.84

a) \(x+\left(-7\right)=-20\)

\(\Rightarrow x=-20+7\)

\(\Rightarrow x=-13\)

Vậy \(x=-13\)

b) \(8-x=-12\)

\(\Rightarrow x=8-\left(-12\right)\)

\(\Rightarrow x=20\)

Vậy \(x=20\)

c) \(|x|-7=-6\)

\(\Rightarrow|x|=-6+7\)

\(\Rightarrow|x|=1\)

\(\Rightarrow\orbr{\begin{cases}x=1\\x=-1\end{cases}}\)

Vậy \(x\in\left\{1;-1\right\}\)

d) \(5^2.2^2-7.|x|=65\)

\(\Rightarrow\left(5.2\right)^2-7.|x|=65\)

\(\Rightarrow10^2-7.|x|=65\)

\(\Rightarrow100-7.|x|=65\)

\(\Rightarrow7.|x|=35\)

\(\Rightarrow|x|=5\)

\(\Rightarrow\orbr{\begin{cases}x=5\\x=-5\end{cases}}\)

Vậy \(x\in\left\{5;-5\right\}\)

e) \(37-3.|x|=2^3-4\)

\(\Rightarrow37-3.|x|=8-4\)

\(\Rightarrow37-3.|x|=4\)

\(\Rightarrow3.|x|=33\)

\(\Rightarrow|x|=11\)

\(\Rightarrow\orbr{\begin{cases}x=11\\x=-11\end{cases}}\)

Vậy \(x\in\left\{11;-11\right\}\)

f) \(|x|+|-5|=|-37|\)

\(\Rightarrow|x|+5=37\)

\(\Rightarrow|x|=32\)

\(\Rightarrow\orbr{\begin{cases}x=32\\x=-32\end{cases}}\)

Vậy \(x\in\left\{32;-32\right\}\)

g)\(5.|x+9|=40\)

\(\Rightarrow|x+9|=8\)

\(\Rightarrow\orbr{\begin{cases}x+9=8\\x+9=-8\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-1\\x=-17\end{cases}}\)

Vậy \(x\in\left\{-1;-17\right\}\)

h) \(-\frac{5}{6}+\frac{8}{3}+\frac{-29}{6}\le x\le\frac{-1}{2}+2+\frac{5}{2}\)

\(\Rightarrow\frac{-5}{6}+\frac{16}{6}+\frac{-29}{6}\le x\le\frac{-1}{2}+\frac{4}{2}+\frac{5}{2}\)

\(\Rightarrow-3\le x\le4\)

Vậy \(-3\le x\le4\)

câu a

x+(-7)=-20

x=-20-(-7)

x=-13

khó quá bn ơi

2b,

a)\(\left(1-\frac{3}{6}^2\right)+\left|\frac{-7}{23}\right|+\left(-\frac{4}{25}\right)\\ =\frac{3}{4}+\frac{7}{23}+\left(-\frac{4}{25}\right)\\ =\frac{2057}{2300}\)

b)\(\sqrt[]{25}-\sqrt[]{100}+\sqrt[]{36}\\ =5-10+6\\ =1\)

c)\(\left(\frac{-31}{37}\right)^5.\left(\frac{37}{62}\right)^5\\ =\left(\frac{-31}{37}.\frac{37}{62}\right)^5\\ =\left(\frac{-1}{2}\right)^2\\ =\frac{1}{4}\)

\(a)5-\left(x-6\right)=4\left(3-2x\right)\)

\(\Leftrightarrow5-x+6=12-8x\)

\(\Leftrightarrow-x+8x=12-5-6\)

\(\Leftrightarrow7x=1\Leftrightarrow x=\frac{1}{7}\)

a) 5-(x-6)=4(3-2x)

<=>5-x-6=12-8x

<=>-x+8x=2-5-6

<=>7x=1

<=>x=1/7

\(b)3-4x\left(25-2x\right)=8x^2+x-300\)

\(\Leftrightarrow3-100x+8x^2=8x^2+x-300\)

\(\Leftrightarrow101x-303=0\)

\(\Leftrightarrow101\left(x-3\right)=0\)

\(\Leftrightarrow x-3=0\Leftrightarrow x=3\)

a)\(3:2 = 1,5\,\,\,\,\,\,\,\,\,\,\,37:25 = 1,48\,\,\,\,\,\,\,\,5:3 = 1,666...\,\,\,\,\,\,1:9 = 0,111...\)

b) \(\frac{3}{2} = 1,5;\,\,\,\,\frac{{37}}{{25}} = 1,48;\,\,\,\,\frac{5}{3} = 1,666...;\,\,\,\frac{1}{9} = 0,111...\)

Chú ý: Các phép chia không bao giờ dừng ta viết ba chữ số thập phân sau dấu phẩy và sau đó thêm dấu ba chấm phía sau.

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