\(\frac{292929-404}{4.797979+909}\)=\(\frac{292525}{4798888}\)=\(\frac{11701}{599861}\)

x = 28 / 87

Kết quả bằng 28 / 87

lời giải đàng hoàng chứ

\(\left(\frac{505}{707}+\frac{222}{333}\right)\)x=\(\frac{404}{909}\)

\(\left(\frac{5}{7}+\frac{2}{3}\right)\)x=\(\frac{4}{9}\)

\(\left(\frac{15}{21}+\frac{14}{21}\right)\)x=\(\frac{4}{9}\)

\(\frac{29}{21}\)x=\(\frac{4}{9}\)

x=\(\frac{4}{9}:\frac{29}{21}\)

x=\(\frac{4}{9}.\frac{21}{29}\)

x=\(\frac{28}{87}\)

Vậy x=\(\frac{28}{87}\)

k mình nha bạn

\(\left(\frac{505}{707}+\frac{222}{333}\right)\cdot x=\frac{404}{909}\)

 =>     \(\left(\frac{5}{7}+\frac{2}{3}\right)\cdot x=\frac{4}{9}\)

=>                     \(\frac{29}{21}\cdot x=\frac{4}{9}\)

=>                               \(x=\frac{4}{9}:\frac{29}{21}\)

=>                              \(x=\frac{28}{87}\)

TK mk nha!

( 505/707+ 222/333) . x = 404/ 909

29/21 . x = 4/9

x= 4/9 : 29/21

x= 4/9 . 21/29

x= 28/87

Vậy x= 28/87

28/87

\(\frac{1717}{2929}=\frac{17.101}{29.101}=\frac{17}{29}\left(1\right)\)

\(\frac{171717}{292929}=\frac{17.10101}{29.10101}=\frac{17}{29}\left(2\right)\)

từ (1) và (2) => đpcm

hai phan so bang nhau

1717/2929 = 17,101/29,101,= 17 /29

\(A=\frac{595959}{454545}-\frac{14141414}{15151515}\)

\(A=\frac{595959:10101}{454545:10101}-\frac{14141414:1010101}{15151515:1010101}\)

\(A=\frac{59}{45}-\frac{14}{15}\)

\(A=\frac{59}{45}-\frac{42}{45}=\frac{17}{45}\)

\(B=\frac{65+891+135+909}{731-47+69-253}\)

\(B=\frac{\left(65+135\right)+\left(891+909\right)}{\left(731+69\right)-\left(47+253\right)}\)

\(B=\frac{200+1800}{800-300}=\frac{2000}{500}=4\)

Giải theo cách lớp 5

\(A=\frac{595959}{454545}-\frac{14141414}{15151515}\\ A=\frac{595959:10101}{454545:10101}-\frac{14141414:1010101}{15151515:1010101}\\ A=\frac{59}{45}-\frac{14}{15}=\frac{17}{45}\)

\(B=\frac{65+891+135+909}{731-47+69-253}=\frac{\left(65+135\right)+\left(891+909\right)}{\left(731+69\right)-\left(47-253\right)}=\frac{200+1800}{731+69-47+253}=\frac{200+1800}{500}=\frac{2000}{500}=4\)

Đáp án là C

Ta có (-909) + 909 = 0

Đáp án cần chọn là: C

Ta thấy 909 và (−909) là hai số đối nhau.

Ta có (−909)+909=0.