a)  \(6^2:4\times3+2\times5^2\)

\(=36:4\times3+2\times25\)

\(=9\times3+50\)

\(=27+50\)

\(=77\)

b)   \(125+70+375+230\)

\(=\left(125+375\right)+\left(70+230\right)\)

\(=500+300\)

\(=800\)

c)   \(150:\left[25\times\left(18-4^2\right)\right]\)

\(=150:\left[25\times\left(18-16\right)\right]\)

\(=150:\left[25\times2\right]\)

\(=150:50\)

\(=3\)

Cảm ơn bạn nhiều

\(-\frac{3}{5}.\frac{11}{7}+\frac{3}{-5}.\frac{4}{7}+\frac{23}{7}\)

\(=\frac{-3}{5}\left(\frac{11}{7}+\frac{4}{7}\right)+\frac{23}{7}\)

\(=\frac{-3}{5}.\frac{15}{7}+\frac{23}{7}\)

\(=\frac{-9}{7}+\frac{23}{7}=2\)

lam cho minh cai

Thực hiện phép tính ( bằng cách hợp lí nếu có thể ) 

A. 2/3 - (- 1/4)+3/5-(+7/45)-(-5/9)+1/12+1/39 

B. 6.(-2/3)^2 - 3(-2/3)^2 - 2 : (-3/2)+4

khó nhìn quá e chỉnh lại đi nha

(125+375) + ( 70+230)

500           +   300

800

6/7+(5/8-3/16):5.-4

=6/7+(10/16-3/16):5.-4

=6/7+7/16:5.-4

=6/7+7/80.-4

=6/7+-28/80

=6/7+7/20

120/140+49/140

=169/140

-1/2+ 2/3 - 3/4 + 4/5

trả lời:

-1/2+ 2/3 - 3/4 + 4/5

=13/60