a: 29+131+237+763

=160+1000

=1160

b: 65+327+15+73

=65+15+327+73

=80+400

=480

c: \(12+54:8-8\)

=12+3-8

=15-8

=7

d: \(45\cdot58+45\cdot42\)

\(=45\cdot\left(58+42\right)\)

\(=45\cdot100=4500\)

e: \(35\cdot34+35\cdot26+40\cdot35\)

\(=35\cdot\left(34+26+40\right)\)

\(=35\cdot100=3500\)

f: \(65\cdot25+65\cdot45+30\cdot65\)

\(=65\cdot\left(25+45+30\right)\)

\(=65\cdot100=6500\)

g: \(750:\left\lbrace32-\left\lbrack2^2+\left(5\cdot3^2-42\right)\right\rbrack\right\rbrace+100\)

\(=\frac{750}{32-\left\lbrack4+5\cdot9-42\right\rbrack}+100=\frac{750}{32-4-45+42}+100\)

\(=\frac{750}{28-3}+100\)

=750:25+100

=30+100

=130

h: \(\left\lbrace630:\left\lbrack16+3\cdot\left(6+3\cdot4\right)\right\rbrack\right\rbrace-1\)

\(=\frac{630}{16+3\cdot\left(6+12\right)}-1=\frac{630}{16+3\cdot18}-1\)

\(=\frac{630}{70}-1\)

=9-1=8

i: \(5871:\left\lbrack928-\left(247-82\right)\cdot5\right\rbrack+2175^0\)

\(=\frac{5871}{928-165\cdot5}+1\)

\(=\frac{5871}{928-825}+1=\frac{5871}{103}+1=57+1=58\)

k: \(375:\left\lbrace32-\left\lbrack4+\left(5\cdot3^2-42\right)\right\rbrack\right\rbrace-14\)

\(=\frac{375}{32-\left\lbrack4+5\cdot9-42\right\rbrack}-14\)

\(=\frac{375}{32-\left\lbrack4+45-42\right\rbrack}-14=\frac{375}{32-\left(4+3\right)}-14=\frac{375}{32-7}-14\)

\(=\frac{375}{25}-14\)

=15-14

=1

35 . 34 + 35 . 38 + 65 . 75 + 65 . 45 + 35 . 34 = 

= 35 . 34 + 35 . 38 + 35 . 34 + 65 . 75 + 65 . 45 

= 35 . ( 34 + 38 + 34 ) + 65 . ( 75 + 45 )

=  35 . 110  + 65 . 110 

= 110 . ( 35 + 65 ) 

= 110 . 100

= 11000

Hok tốt!!!!!!!!!!!!!

a) Tính bằng cách hợp lí nhất :

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

= 35 . 34 + 35 . 38 + 35 . 34 + 65 . 75 + 65 . 45

= 35 . ( 34 + 38 + 34 ) + 65 . ( 75 + 45 )

= 35 . 106 + 65 . 120

= 3710 + 7800

= 11510

3 . 25 . 8 + 4 . 37 . 6 + 2 . 38 . 12

= 3 . 8 . 25 + 4 . 6 . 37 + 2 . 12 . 38

= 24 . 25 + 24 . 37 + 24 . 38

= 24 . ( 25 + 37 + 38 )

= 24 . 100

= 2400

b) Tìm số tự nhiên x, biết :

( x - 5 ) ( x + 7 ) = 0

\(\Rightarrow\orbr{\begin{cases}x-5=0\\x+7=0\end{cases}\Rightarrow\orbr{\begin{cases}x=5\\x=-7\end{cases}}}.\)

Vậy .......

35.(34+38)+65.(75+45)

35.72 + 65.120

2520+7800

10320

10320

35 * 34 + 35 * 34 + 65 * 75 + 65 * 45

= 34* ( 35+35) + 65* ( 75 + 45)

= 34 * 70 + 65* 120

= 2380 + 7800

= 10180

\(=35.\left(34+34\right)+65.\left(75+45\right)\)

\(=35.68+65.120=2380+7800=10180\)

9063                 

35 . 34 + 35+38 +65 +75 +65 . 45 

= 35 .( 34 + 1 ) + 38 + 65 ( 75 + 45 )

= 35² + 38 + 7800

= 9063 
Chúc bạn học tốt 

35 x 34 + 35 x 65 + 65 x 75 + 65 x 45

= ( 35 x 34 + 35 x 65 ) + ( 65 x 75 + 65 x 45 )

= 35 x ( 34 + 65 ) + 65 x ( 75 + 45 )

= 35 x 99 + 65 x 120

= 3465 + 7800

= 11265

\(35.34+35.65+65.75+65.45\)

=\(35.\left(34+65\right)+65.\left(75+45\right)\)

= 35. 99 +65.120

=3465 + 7800

= 11265

15+45+25+35+65+75+85+95

=15+25+35+45+65+75+85+95

=(15+25+35+45)+(65+75+85+95)

=120                 +  320

=440

tick nha Đức Dương

12000 nha

35 x 34 + 35 x 86 + 65 x 75 + 65 x 45

= 1190 +  35 x 86 + 65 x 75 + 65 x 45

= 1190 +   3010     + 65 x 75 + 65 x 45

=  1190 +   3010     + 4875    + 65 x 45

=   1190 + 3010       + 4875   +  2925

=   12000