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

\(a,\dfrac{x}{4}=\dfrac{15}{20}\\ \Rightarrow\dfrac{x}{4}=\dfrac{3}{4}\\ \Rightarrow x=3\\ b,\dfrac{15}{x}=\dfrac{25}{35}\\ \Rightarrow\dfrac{15}{x}=\dfrac{5}{7}\\ \Rightarrow\dfrac{15}{x}=\dfrac{15}{21}\\ \Rightarrow x=21\\ c,\dfrac{x}{5}=\dfrac{26}{65}\\ \Rightarrow\dfrac{x}{5}=\dfrac{2}{5}\\ \Rightarrow x=2\\ d,\dfrac{3}{x}=\dfrac{51}{85}\\ \Rightarrow\dfrac{3}{x}=\dfrac{3}{5}\\ \Rightarrow x=5\)

a,x4=1520⇒x4=34⇒x=3b,15x=2535⇒15x=57⇒15x=1521⇒x=21c,x5=2665⇒x5=25⇒x=2d,3x=5185⇒3x=35⇒x=5

4a) \(\frac{x}{36}=\frac{3}{4}\)

\(\Rightarrow\frac{x}{36}=\frac{27}{36}\)

\(\Rightarrow x=27\)

4b) 33 + x = 71 - 26

33 + x = 45

x = 45 - 33

x = 12

4c) x * (3,5 + 1,5) = 10

x * 5 = 10

x = 10 ; 5 = 2

4,

\(a,\frac{x}{36}=\frac{24}{32}\)

\(=>\frac{x}{36}=\frac{3}{4}=\frac{27}{36}\)

\(=>x=27\)

\(b,71-\left(33+x\right)=26\)

\(=>-\left(33+x\right)=26-71=-45\)

\(=>33+x=45\)

\(=>x=12\)

\(c,3,5\cdot x+1,5\cdot x=10\)

\(>x\cdot\left(3,5+1,5\right)=10\)

\(=>x\cdot5=10\)

\(=>x=2\)

. là nhân nha

4. 

a) x/36 = 24/32

24/32 = 3/4 = 27/36

=> x = 27

b) 71 - ( 33 + x ) = 26

33 + x = 71 - 26

33 + x = 45

x = 45 - 33

x = 12

c) 3, 5 . X + 1, 5 . x = 10

x( 3, 5 + 1, 5 ) = 10

x . 5 = 10

x = 10 : 5

x = 2

5.

a) 4, 63 . 7, 8 + 7, 8 + 7, 8 . 4, 32

= 7, 8. ( 4, 63 + 4, 32 + 1 )

= 7, 8 . 9, 95

= 77, 61

b) 35 . 34 + 35 . 86 + 65 . 75 + 65 . 45

= 35( 34 + 86 ) + 65( 75 . 45 )

= 35 . 120 + 65 . 120

= 120 . ( 35 + 65 )

= 120 . 100

= 12 000

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 .......

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

Hok tốt!!!!!!!!!!!

C

C

C

bằng 9075 đấy . tk mk nha

9075 nha bn

9075 nha bạn ! kb nha !

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

= ( 34 x 35 + 35 x 86 ) + ( 65 x 75 + 65 x 45 )

= 35 x ( 34 + 86 ) + 65 x ( 75 + 45 )

= 35 x 120 + 65 x 120

= 120 x ( 35 + 65 )

= 120 x 100

= 12000

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

=35 x (34+86) + 65 x (75+45)

=35 x 120 + 65 x 120

=120 x (35+65)

=120 x 101

=12120

k mình nhé Vũ Thị Minh Thư

34x35+65x75+35x86+65x45=12000

a)=35x(34+38)+72x(65+65)

=35x72+72x130

=72x(35+130)

=72x165

=11880

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

= 5 x 17 x 10 + 65 x (75 + 45) - 7 x 43 x 10

= 85 x 10 + 780 x 10 - 301 x 10

= 10 x (85 + 780 - 301)

= 10 x 564

= 5640