a) (26-6)*(-4)+31*(-7-13)

=-80+-620

=-700

hacker 2k6

Câu 1:

a; x/7 = - 9/14

x = - 9/14 x 7

x = - 9/2

Vậy x = -9/2

b; - 16/36 = - y/4

-4/9 = - y/4

y = -4/9 x (-4)

y = 16/9

Vậy y = 16/9

Câu 1c:

-5/12 = x/60

x = -5/12 x 60

x = - 25

Vậy x = - 25

d: -4/8 = x/-10 = -7/y

-4/8 = x/-10

x = -4/8 x (-10)

x = 5

-4/8 = -7/y

y = - 7 : (-4/8)

y = 7 x 8/4

y = 14

Vậy (x; y) = (5; 14)

a, \(=\frac{27}{45}+\frac{-25}{45}\)

\(=\frac{2}{45}\)

b, \(=\frac{4}{13}+\frac{-4}{13}\)

\(=0\)

c, \(=\frac{1}{5}+\frac{-4}{5}\)

\(=\frac{-3}{5}\)

Nhớ tích hộ mình nhaaaaaaa!!!!!

a,30-7-8+9-11

=(30-7-8-11)+9=4+9=13

b,40-2+(-40)-2+4

=(40-40)+(4-2-2)=0

c,15-2+(-7)-9+(-11)

=15-(2+7+9+11)=15-29=-14

d,28-1+35-36-27

=(28-27)(+(35-36)-1=1-1-1=-3

có j ko hiểu thì add fr mình nha :)))

45 - 5.(11 + 9)

= 45 - 55 - 45 = - 55

b) mk chỉnh lại đề câu b)

  40.(29 - 35) - 29.(40 - 35)

= 40.29 - 40.35 - 29.40 + 29.35

= 35.(29 - 40) = - 385 

a) 45-5.(11+9)

=(45-5).20

=40.20

=80

a, -270/450=-3/5       b,                  c,8,3       

a: \(\dfrac{5}{7}=\dfrac{5\cdot11}{7\cdot11}=\dfrac{55}{77}\)

\(\dfrac{9}{11}=\dfrac{9\cdot7}{11\cdot7}=\dfrac{63}{77}\)

b: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot9}{7\cdot9}=\dfrac{54}{63}\)

\(-\dfrac{12}{54}=\dfrac{-2}{9}=\dfrac{-2\cdot7}{9\cdot7}=-\dfrac{14}{63}\)

c: \(\dfrac{-11}{30}=\dfrac{-11\cdot4}{30\cdot4}=\dfrac{-44}{120}\)

\(\dfrac{-17}{-40}=\dfrac{17}{40}=\dfrac{17\cdot3}{40\cdot3}=\dfrac{51}{120}\)

d: \(\dfrac{36}{42}=\dfrac{6}{7}=\dfrac{6\cdot3}{7\cdot3}=\dfrac{18}{21}\)

\(\dfrac{-12}{36}=\dfrac{-1}{3}=\dfrac{-1\cdot7}{3\cdot7}=\dfrac{-7}{21}\)