Question

2/25.

C)-1/4+-5/17.[1/3:20/17.

5.tính nhanh a)-3/7+5/13+-4/7

B) 5/9+7/12+4/9

C) 9/10.-7/8+9/10.-1/8

D 7/19.8/11+7/19.3/11+12/19.

6 . tim x

A) X+1/7=-2/3.

B)5/9+7/12+4/9.

C)-1/3.x5/7.

D)x:-5/9=9/10

E)x/3=2/3+-1/7.

7)qua da hau nang bao nhieu kilogam neu biet 2/3qua dau nang .1, 2 phan 3 kg?

8biet ti so phan tram nUoc tong dua cHuot la 97,2%tinh luong nuoc trong 4 kg dua chuot.

Answer 1

Bài 6:

a: \(x=-\dfrac{2}{3}-\dfrac{1}{7}=\dfrac{-14-3}{21}=\dfrac{-17}{21}\)

d: \(x=\dfrac{9}{10}\cdot\dfrac{-5}{9}=\dfrac{-1}{2}\)

e: \(\Leftrightarrow x\cdot\dfrac{1}{3}=\dfrac{14}{21}-\dfrac{3}{21}=\dfrac{11}{21}\)

=>x=11/7