Tìm x

3x + 7x = 72

(3+7)x = 72

21.x = 72

     x = 72:21

     x = 72/21

     x = 24/7

câu tính nhanh sai đề hay sao í

co minh ra nen minh nghi ko sai dau a

25.32+25.43+25.37

=25.(32+43+37)

=25×112

=2800

k mik nha

thank you

25.32+25.43+25.37 =  25.32+25.43+25.25+25.12
= 25.(32+43+25) + 25.12 = 25.100 + 50.6 = 2500+300 = 2800

  25.37+137.25

=25.(37+137)

=25.174

=4350

hình như nhầm đề bài rồi 

25 . 37 + 137 . 25

= 25 . ( 37 + 137 )

= 25 . 174

= 4350

25 . 37 + 137 . 25

= 25 . ( 37 + 137 )

= 25 . 174

= 4350

25.37+137.25

=25(37+137)

=25.174

=4350

Bạn áp dụng tính chất phân phối là ra ngay thôi!!!

25.37+137.25

= 25. (37+137)

= 25.174

= 4350

Giải:

\(25.37+137.25\)

\(=25.\left(37+137\right)\)

\(=25.174\)

\(=4350\)

Vậy ...

a, 27.26+27.64

=27.(26+64)

=27.90

=2430

b,25.37+25.63-150

=25.(37+63)-150

=25.110-150

=2750-150

=2600

c,425.7.4=170.60

=1700.7=170.10.6

=1700.7-1700.6

=1700.(7-6)

=1700

d,0.9.14+6.17.12+19.4.18

=0+6.17.12+19.4.18

=6.3.4.17+19.4.18

=18.4.17+19.4.18

=18.4.(17+19)

=72.36=2592

\(=27\cdot100-700=2000\)

\(=27.\left(43+57\right)+\left(-700\right)=2700+\left(-700\right)=2000\)

=27⋅100−700=2000

Đặt
\(A=\frac{5}{2.7}+\frac{5}{7.12}+\frac{5}{12.17}+\frac{5}{17.22}+\frac{5}{22.27}+\frac{5}{27.32}+\frac{5}{32.37}\)

\(A=\frac{1}{2}-\frac{1}{7}+\frac{1}{7}-\frac{1}{12}+\frac{1}{12}-\frac{1}{17}+\frac{1}{17}-\frac{1}{22}+\frac{1}{22}-\frac{1}{27}+\frac{1}{27}-\frac{1}{32}+\frac{1}{32}-\frac{1}{37}\)

\(A=\frac{1}{2}-\frac{1}{37}=\frac{35}{74}\)

\(=\frac{1}{2}-\frac{1}{7}+\frac{1}{7}-\frac{1}{12}+\frac{1}{12}-\frac{1}{17}+...+\frac{1}{32}-\frac{1}{37}\)

\(=\frac{1}{2}-\frac{1}{37}\)

\(=\frac{37}{74}-\frac{2}{74}=\frac{35}{74}\)

\(=\frac{1}{2}.\frac{1}{7}+\frac{1}{7}.\frac{1}{12}...+\frac{1}{32}.\frac{1}{37}\)

= \(\frac{1}{2}+\frac{1}{37}\)

= \(\frac{37}{74}+\frac{2}{74}\)

\(\frac{39}{74}\)

tíck mik nha, mik nhanh nhất

- 43. 54 – 46. 27 + 27.32

= -43 . 27. 2 - 46 . 27 + 27 . 32

= 27(-86 - 46 + 32)

= 27 . 100

= 2700

-25 . 37 + 137 . 25

= 25 . ( -37 ) + 137 . 25

= 25 . [ ( -37 ) + 137 ]

= 25 . 100

= 2500

-25.37+137.25

=-925+3425

=2500

-25.37 + 137.25

= 25 . ( -37 ) + 137 . 25

= 25 . [ ( -37 ) + 137 ]

= 25 . 100

= 2500