tong  hai  van  toc  la

     50 + 25  = 75 (km /gio )

Quang đuông Ab  la

    7,5 x 75 =562,5 (km)

       đ/s 562,5 km

tổng vận tốc là

25 + 50 = 75 km/giờ

quãng đường AB là

75 x 7,5 = 562,5 km

đáp số 562,5 km

y x 11 - y = 10.5

y x ( 11 - 1 ) = 10.5

y x 10 = 10.5

y = 10.5 : 10

y = 1.05

Bn ơi, đầu bài là 10,5 hay 10x5 thế

\(\Delta\)COE=\(\Delta\)COD(ch-gn)=>OE=OD

\(\Delta\)BOF=\(\Delta\)BOD(ch-gn)=>OD=OF

Suy ra: OD=OE=OF

b) mình nghĩ là ko bằng

\(\left(\frac{2}{11}+\frac{1}{3}\right)\cdot x=\left(\frac{1}{7}-\frac{1}{8}\right)\cdot56\)

\(\Rightarrow\left(\frac{6}{33}+\frac{11}{33}\right)\cdot x=\left(\frac{8}{56}-\frac{7}{56}\right)\cdot56\)

\(\Rightarrow\left(\frac{6+11}{33}\right)\cdot x=\left(\frac{8-7}{56}\right)\cdot56\)

​\(\Rightarrow\frac{17}{33}\cdot x=\frac{1}{56}\cdot56\)​

\(\Rightarrow\frac{17}{33}\cdot x=1\)

\(\Rightarrow x=1:\frac{17}{33}=\frac{33}{17}\)

Vậy x = 33/17

\(\left[\frac{2}{11}+\frac{1}{3}\right]\cdot x=\left[\frac{1}{7}-\frac{1}{8}\right]\cdot56\)

\(\Rightarrow\left[\frac{2\cdot3}{33}+\frac{1\cdot11}{33}\right]\cdot x=\left[\frac{8}{56}-\frac{7}{56}\right]\cdot56\)

\(\Rightarrow\left[\frac{6}{33}+\frac{11}{33}\right]\cdot x=\frac{1}{56}\cdot56\)

\(\Rightarrow\frac{17}{33}\cdot x=1\)

\(\Rightarrow x=1:\frac{17}{33}=1\cdot\frac{33}{17}=\frac{33}{17}\)

1+1=2 nha ^_^

ả lời : 1+1=2

Hok_Tốt

Tk mk nha 

#Thiên_Hy