a) \(x-285\div35=5\times54\)

\(x-\dfrac{57}{7}=270\)

\(x=\dfrac{1947}{7}\)

b) \(\left(x+120\right)\div20=8\)

\(x+120=160\)

\(x=40\)

c) \(\left(x+5\right)\times3=300\)

\(x+5=100\)

\(x=95\)

d) \(\left(x+100\right)\times4=800\)

\(x+100=200\)

\(x=100\)

a) \(x-285:35=5x54\)

\(x-\dfrac{57}{7}=270\)

\(x=270+\dfrac{57}{7}=\dfrac{1890}{7}+\dfrac{57}{7}=\dfrac{1947}{7}\)

b) \(\left(x+20\right):20=8\)

\(\left(x+20\right)=8x20\)

\(x+20=160\)

\(x=160-20=140\)

c) \(\left(x+5\right)x3=300\)

\(x+5=300:3\)

\(x+5=100\)

\(x=100-5=95\)

d) \(\left(x+100\right)x4=800\)

\(x+100=800:4\)

\(x+100=200\)

\(x=200-100=100\)

a) 135 - 35 : 5 = 100 : 5 = 20 

b) 246 + 54 x 2 = 246 + 108 = 354

c) 135 - 35 : 5 = 135 - 7= 128 

d) 246 + 54 x 2 = 300 x 2= 600

x - 280 : 35 = 5 . 54 

x - 280 : 35 = 270

x  - 280        = 270 x 35

x - 28           = 9450

x                  = 9450 + 280

x                  = 9730

cho mk nhe

x - 280 : 35 = 5 . 54

x - 280 : 35 = 270

x - 280 = 270 . 35

x - 280 = 9450

x = 9450 + 280

x = 9730

Vậy x = 9730

Nhớ k nha mik lm đúng rồi!

Ta có: \(x-280:35=5.54\)

\(\Rightarrow x-8=270\)

\(\Rightarrow x=270+8\)

\(\Rightarrow x=278\)

Vậy x = 278

nha m.n

a ) \(=\frac{35\cdot42}{5\cdot2}=\frac{7\cdot5\cdot2\cdot21}{5\cdot2}\)

\(=\frac{7\cdot21}{1}=147\)

b) \(=\frac{54\cdot35}{7\cdot9}\)

\(=\frac{6\cdot9\cdot7\cdot5}{7\cdot9}\)

\(=\frac{6\cdot5}{1}=30\)

35x42/5x2= 5x7x2x12/5x2=84

54x35/7x9=6x9x7x5/7x9=30

x=24

x=3

x=9

x=75

\(\frac{3}{7}=\frac{x}{56}=\frac{24}{56}=>x=24\)

\(\frac{x}{5}=\frac{21}{35}=\frac{x}{5}=\frac{3}{5}=>x=3\)

\(\frac{42}{54}=\frac{7}{x}=\frac{7}{8}=\frac{7}{x}=>x=8\)

\(\frac{35}{x}=\frac{7}{15}=\frac{35}{x}=\frac{35}{75}=>x=75\)

1) Áp dụng tính chất dãy tỉ số bằng nhau ta có:

\(\dfrac{x}{5}=\dfrac{y}{7}=\dfrac{x+y}{5+7}=\dfrac{48}{12}=4\)

\(\dfrac{x}{5}=4\Rightarrow x=20\\ \dfrac{y}{7}=4\Rightarrow y=28\)

2) Áp dụng tính chất dãy tỉ số bằng nhau ta có:

\(\dfrac{x}{4}=\dfrac{y}{-7}=\dfrac{x-y}{4+7}=\dfrac{33}{11}=3\)

\(\dfrac{x}{4}=3\Rightarrow x=12\\ \dfrac{y}{-7}=3\Rightarrow y=-21\)

a, 568 + 568 x 135 - 568 x 36

= 568 x ( 1 + 135 - 36)

= 568 x 100

56 800

b, 17 x 49 + 49 x 37 + 54 x 26 + 54 x 25

=  49 x ( 17 + 37) + 54 x ( 26 + 25 )

= 49 x 54 + 54 x 51

= 54 x ( 49 + 51)

= 54 x 100

= 5 400

c,   14 x 35 x 5 + 10 x 25 x 7 + 20 x 70

 =    ( 2 x 35) x ( 7 x 5)  + ( 10 x 7) x 25 + 20 x 70

= 70 x 35 + 70 x 25 + 20 x 70

= 70 x ( 35 + 25 + 20)

= 70 x 80

= 5 600 

a) 568 + 568 x 135 - 568 x 36

= 568 x ( 1+1+135-1-36 )

=568 x 100

=5680

b) 17 x 49 + 49 x 37 + 54 x 26 + 54 x 25

= 49 x ( 17 + 37 ) + 54 x ( 26 + 25 )

= 49 x 54 + 54 x 51

= 54 x ( 49 + 51 )

= 54 x 100

= 5400

c) 14 x 35 x 5 + 10 x 25 x 7 + 20 x 70

= 70 x 35 + 10 x 25 x 7+ 20 x 70

= 70 x 35 + 250 x 7 + 20 x 70

= 70 x 35 + 70 x 25 + 20 x 70

= 70 x (35+25+20)

= 70 x 80

= 5600

a ; 29 x 64 +116 x 34 

= 29  x 2 x 32 + 116 : 2 x 2 x 34 

= 58 x 32 + 58 x 68 

= 58 ( 32 + 68)

= 58 x 100 

= 5800

b, 136 x 68 + 16 x 272 

=  136 x 68 + 16 x 2 x 136

= 136 x 68 + 136 x 32

= 136 ( 68 + 32)

= 136 x 100

= 13600

a) x = -11

b) x = 2

c) x = -5

d) x = 5

e) x = 3 hoặc x = 7        

f) x = -1 hoặc x = 9