Bài 1 : 

12/19 + 4 = 88/19

1234 + 9800 - 9700 = 1334

Bài 2:

10/32  <  9/8

21/14  >  20/12

1)

a)\(\frac{12}{19}\)+4=\(\frac{12}{19}\)+ \(\frac{76}{19}\)=\(\frac{88}{19}\)                                 1234+9800-9700 

                                                                                                   =1234+100=1334

2)\(\frac{10}{32}\)<\(\frac{9}{8}\)                                      \(\frac{21}{14}\)<\(\frac{20}{12}\)

231234+23421-[123-1234]

= 254655 - (-1111)

= 255766

255766

\(\frac{12}{67}\)+ \(\frac{34}{54}\)= \(\frac{1463}{1809}\)

Nhớ k mk đấy !!!!!!!!!!!

12/67 + 34/54 = 12/67 + 12/27 = 12x27/67x27 + 34x67/27x67 = 324/1809 + 2278/1809 = 324 + 2278/1809 = 2602/1809

vậy 12/67 + 34/54 = 2602/1809

2000 nhe aikatsu ichigo.

k minh nhe. Sau do ket ban nhe.

\(1234+766=2000\)

k cho mik nha mik xin đó

Ta có \(x.a=b\)

\(x=b:a\)

Do đó \(-\frac{3}{5}.x=\frac{5}{6}\)

\(x=\frac{5}{6}:\frac{-3}{5}\)

\(x=-\frac{1}{2}\)

Tương tự 

2. \(x=\frac{6}{8}:\frac{2}{4}=\frac{3}{2}\)

Bạn tự làm câu 3

1.\(\frac{-3}{5}\).x=\(\frac{5}{6}\)

x=\(\frac{5}{6}\):\(\frac{-3}{5}\)

x=\(\frac{-25}{18}\)

2.\(\frac{2}{4}\):x=\(\frac{6}{8}\)

\(\frac{1}{2}\):x=\(\frac{3}{4}\)

x=\(\frac{1}{2}\):\(\frac{3}{4}\)

x=\(\frac{2}{3}\)

3.\(\frac{67}{89}\).x=\(\frac{12}{13}\)

x=\(\frac{12}{13}\):\(\frac{67}{89}\)

x=\(\frac{1068}{871}\)

K MIK NHÉ

tớ k cậu rồi nha 

\(\frac{1290}{7}\)

k mình mình k lại

1236 nha pham thi huong