a) 35 x 12 + 65 x 13

= 35 x 12 + 65 x (12+1)

=35 x 12 + 65 x 21 + 65

=12 x (65 + 35) + 65

= 12 x 100 + 65

= 1200 + 65

= 1265

b) (37 x 13 -13) : (24 + 37 x 12)

= [ 37 x (12+1) - 13 ] :  (24 + 37 x 12)

=( 37 x 12 + 37 - 13) : ( 24 +37 x 12)

=( 37 x 12 +24) : (24 + 37 x 12)

=\(1\)

Ta có nhận xét phần b hai tích chia cho nhau mà 2 tích giống nhau vậy kết quả là \(1\)

35 x 12 + 65 x 13 = 1265

( 37 x 13 - 13) : (24 + 37 x 12) = 1

a) 35 x 12 + 65 x 13 = 420 + 845

                              = 1265

b) ( 37 x 13 - 13 ) : (24 + 37 x 12) = 468 : 468

                                                 = 1

b/ 35.12+65.(12+1) 
=35.12+35.12+65 
=(35+65).12+65=1200+65=1265 

6305, nhớ tích bạn nha

1265 k cho mình nha

35 x 12 + 65 x 13

=  ( 35 + 65 ) x ( 12 + 13)

= 100 x 25

=2500

a) 19 x 64 + 76 x 34 = 19 x 64 + 19 x 4 x 34 = 19 x (64 + 4 x 34) = 19 x 200 = 3800

b) 35 x 12 + 65 x 13 = 35 x 12 + 65 x 12 + 65 = 12 x (35 + 65) + 65 = 12 x 100 + 65 = 1265

c) 136 x 68 + 16 x 272 = 136 x 68 + 16 x 2 x 136 = 136 x (68 + 16 x 2) = 136 x 100 = 13600

cái này làm sao tính nhah đc

a) 19 x 64 + 76 x 34 = 19 x 64 + 19 x 4 x 34 = 19 x (64 + 4 x 34) = 19 x 200 = 3800

b) 35 x 12 + 65 x 13 = 35 x 12 + 65 x 12 + 65 = 12 x (35 + 65) + 65 = 12 x 100 + 65 = 1265

c) 136 x 68 + 16 x 272 = 136 x 68 + 16 x 2 x 136 = 136 x (68 + 16 x 2) = 136 x 100 = 13600

35 x 12 + 65 x 13 = 35 x 12 + 65 x 12 + 65 = 12 x ( 35 + 65 ) + 65 = 12 x 100 + 65 = 1200 + 65 = 1265

35x12+65x13=420+845=1265

tk cho mk nha

35 x 12 + 65 x 13=1265

a) 3800

b) 1265

c) 13600

a) 19 . 64 + 76 .34 = 38. 32 + 38 . 68
                                  = 38 . (32 + 68) = 38 .100 = 3800
b) 35 . 12 + 65 . 13 = 35 . 12 + 65 . (12 + 1)
                                   = 35 . 12 + 65 . 12 + 65 = 12 . (35 + 65) + 65
                                   = 1200 + 65 = 1265.
c) 136 . 68 + 16 . 272 = 136 . 68 + 32 .136
                                       = 136 . (66 + 32) = 136 . 100 = 13600

k mik nha!

\(a,19\times64+76\times34.\)

\(=38\times32+38\times68\)

\(=38\times\left(68+32\right)\)

\(=38\times100\)

\(=3800\)

\(b,35\times12+65\times13\)

\(=35\times12+65\times\left(12+1\right)\)

\(=35\times12+65\times12+65\)

\(=12\times\left(35+65\right)+65\)

\(=12\times100+65\)

\(=1265\)

\(c,136\times68+16\times272\)

\(=136\times68+32\times136\)

\(=136\times\left(32+68\right)\)

\(=136\times100\)

\(=13600\)

A.35 x 34 + 35 x 38 + 65 x 75 + 65 x 45

Câu này không tính hợp lí được

B. 12x 53 + 53 x 172 - 53 x 84

= 53 x (12 + 172 - 84)

= 53 x 100

= 5300

C. 36 x 28 + 36 x 82 + 64 x 69 + 64 x 41

= 36 x (28+82) + 64 x (69+41)

= 36 x 110 + 64 x 110

= (36+64) x 110

= 100 x 110

= 11 000

D. A = 1+2+3+...+100

= (1+ 100) x 50

= 101 x 50

= 5050

E. B =17+19+...+101+103

= (103 +17) x [(103 - 17):2 + 1]

= 120 x 44

=5280

G. D= 3x (12+13+14+15) + 3x(8+7+6+5)

= 3 x (5+6+7+8+12+13+14+15)

= 3 x (20 x 4)

= 3 x 80

=240

a) 10320

b) 5300

c) 11000

d) 5050

e) 2460

g)  240

\(165-\left(35:x+3\right).19=13\)

\(\Rightarrow\left(35:x+3\right).19=165-13\)

\(\Rightarrow\left(35:x+3\right).19=152\)

\(\Rightarrow35:x+3=152:19\)

\(\Rightarrow35:x+3=8\)

\(\Rightarrow35:x=5\Rightarrow x=7\)

em cám ơn chị ạ