a, \(\frac{x}{13}=\frac{35}{91}\)

\(\frac{x}{13}=\frac{5}{13}\rightarrow x=5\)

b, Cậu xem lại đb xem có nhầm ko

Nếu đb là \(9+x=13-x\)

\(\rightarrow2x=4\rightarrow x=2\)

c, Cậu cx xem lại đb ik

a, \(\frac{x}{13}=\frac{35}{91}\)
=> x = 35.13 : 91 
=> x = 5 
b ) \(\frac{x}{13}-x=\frac{5}{6}-9=\frac{-49}{6}\)
=> \(\frac{x-13x}{13}=\frac{-49}{6}\)
=> -12x . 6 = -49 . 13 
=> -12x . 6 = - 637 
=> -12x = -637 : 6 =\(\frac{-637}{6}\)
=> x = \(\frac{-637}{6}:-12=\frac{-637}{72}\)
c, \(x+\frac{x}{5}.7,5+\frac{x}{2}.9=315\)
\(x+\frac{7,5x}{5}+\frac{9x}{2}=315\)
\(x+\frac{60x}{10}=315\)
\(x+6x=315\)
\(7x=315\Rightarrow x=315:7=45\)
d, \(\frac{2}{3}.x+\frac{1}{2}=\frac{9}{10}-\frac{1}{5}\)
\(\frac{2}{3}x+\frac{1}{2}=\frac{7}{10}\)
\(\frac{2}{3}x=\frac{7}{10}-\frac{1}{2}=\frac{1}{5}\)
\(x=\frac{1}{5}:\frac{2}{3}=\frac{3}{10}\)

mình mới đọc câu a thôi nhé

x=5

a)x=5 nha ban

a, \(\dfrac{x}{13}=\dfrac{35}{91}\Leftrightarrow\dfrac{x}{13}=\dfrac{5}{13}\Leftrightarrow x=5\)

b, \(\dfrac{9+x}{13-x}=\dfrac{5}{6}\Leftrightarrow\dfrac{9+x}{13-x}=\dfrac{10}{12}\Leftrightarrow x=1\)

@đỗ hương giang

a.

\(\dfrac{x}{13}=\dfrac{35}{91}\)

\(\Rightarrow x=\dfrac{35.13}{91}=5\)

Vậy x = 5

b.

\(\dfrac{9+x}{13-x}=\dfrac{5}{6}\)

\(\Rightarrow\dfrac{9+x}{13-x}=\dfrac{10}{12}\)

\(\Rightarrow\dfrac{x=10-9}{13-12=x}\Rightarrow x=\dfrac{1}{1}=1\)

Vậy x =1

c.

x + x : 5 . 7,5 + x : 2.9 = 315

\(\Rightarrow x+\dfrac{x}{5}7,5+\dfrac{x}{2}9=7x\)

\(\Rightarrow7x=3^3.5\)

\(\Rightarrow7x=135\)

\(\Rightarrow x=\dfrac{135}{7}\)

Vậy x = \(\dfrac{135}{7}\)

Chúc bạn học tốt!!!

a) Ta có : \(\frac{35}{91}\)= \(\frac{5}{13}=\frac{x}{13}\Rightarrow x=5\)

b, ta có

<=>6 (9+x)=5 (13-x)

<=>54+6x=65-5x

<=>6x+5x=65-54

<=>11x=11

<=>x=1

a)35/91=x/13.Vì 91:13=7,suy ra x=35:7=5.

\(\frac{315}{316}\cdot\frac{316}{314}\cdot\frac{316}{315}\cdot\frac{317}{313}=\frac{315.316.316.317}{316.314.315.313}=\frac{1.1.316.317}{1.314.1.313}=\frac{100172}{98282}\)

Ta có : \(\frac{3}{2}\times\frac{4}{5}\times\frac{2}{3}\)

\(=\frac{3}{2}\times\frac{2}{3}\times\frac{4}{5}=1\times\frac{4}{5}\)

\(=\frac{4}{5}\)

\(\frac{4}{5}\) nhé bn

1: =-2/9(15/17+2/17)=-2/9

2: \(=\dfrac{-6}{3}+\dfrac{-21}{90}\)

=-2-7/30=-67/30

3: \(=\dfrac{3}{4}\cdot\dfrac{7}{5}+\dfrac{9}{7}\cdot\dfrac{3}{2}\)

=21/20+27/14=417/140

4: =-25/13(5/19+14/19)=-25/13

5: =-7/5-45/21=-7/5-15/7=-124/35

1: =-2/9(15/17+2/17)=-2/9

2: =34⋅75+97⋅32=34⋅75+97⋅32

=21/20+27/14=417/140

4: =-25/13(5/19+14/19)=-25/13

5: =-7/5-45/21=-7/5-15/7=-124/35