\(\left(100+58\right)\times58+\left(200-42\right)\times12\)

\(=158\times58+158\times12\)

\(=158\times\left(58+12\right)\)

\(=158\times70=11060\)

\(128\times72+14\times256\)

\(=128\times72+14\times2\times128\)

\(=128\times\left(72+28\right)\)

\(=128\times100=12800\)

\(157\times99+123+34\)

\(=157\times99+157\times1\)

\(=157\times\left(99+1\right)\)

\(=157\times100=15700\)

\(67+98\times45+23\)

\(=98\times45+90\)

\(=98\times45+45\times2\)

\(=45\times\left(98+2\right)\)

\(=45\times100=4500\)

     -45:(3x-17)=3^2

⇒ -45:(3x-17)= 9

⇒ 3x-17         =-45:9

⇒3x-17          =-5

⇒3x               =-5+17

⇒3x               =12

⇒ x                = 12:3=4

Vậy: x=4

99 - 3(x + 17) = 45

=> 3(x + 17) = 99 - 45

=> 3x + 51 = 54

=> 3x = 54 - 53

=> 3x = 3

=> x = 3 : 3

=> x = 1

vậy_

a,99-3x-51=45

3x=45+51-99

3x=-3

x=-1

b,x⁵:8=4

x⁵=32

x=2

c,3.x³=375

x³=125

x=5

d,12.x-33=3⁵

12x=276

x=23

e,4x⁵=128

x⁵=32

x=2

g,2^x:4=16

2^x=64

x=6

\(12x-33=3^5\)

\(12x-33=243\)

\(12x=243+33\)

\(12x=276\)

\(x=276:12\)

\(x=23\)

Vậy x = 23

\(4.x^5=128\)

\(x^5=128:4\)

\(x^5=32\)

\(x^5=2^5\)

\(\Rightarrow x=2\)

Vậy x = 2

a. \(\Leftrightarrow\) (3.x+4):12 = 19-17

   \(\Leftrightarrow\)(3.x+4):12 = 2

\(\Leftrightarrow\)3.x+4 = 24   \(\Leftrightarrow\)3.x = 20   \(\Leftrightarrow\)x = \(\frac{20}{3}\)

b. \(\Leftrightarrow\)45: (2.x+1) = 3 \(\Leftrightarrow\)2.x+1 = 15 \(\Leftrightarrow\)2.x = 14 \(\Leftrightarrow\)x = 7

c. \(\Leftrightarrow\)72.(x+1) = 360 \(\Leftrightarrow\)x+1 = 5\(\Leftrightarrow\)x = 4

d.\(\Leftrightarrow\)(2.x+3).11 = 253\(\Leftrightarrow\)2.x+3 = 23\(\Leftrightarrow\)2.x = 20\(\Leftrightarrow\)x = 10

-35 

ko biết 

a ) 

\(x+\frac{12}{15}=\frac{7}{5}\)

\(\Rightarrow x=\frac{7}{5}-\frac{12}{15}\)

\(\Rightarrow x=\frac{7}{5}-\frac{4}{5}\)

\(\Rightarrow x=\frac{3}{5}\)

Vậy \(x=\frac{3}{5}\)

b ) 

\(x-\frac{6}{8}=\frac{3}{15}\)

\(\Rightarrow x-\frac{3}{4}=\frac{1}{5}\)

\(\Rightarrow x=\frac{1}{5}+\frac{3}{4}\)

\(\Rightarrow x=\frac{4}{20}+\frac{15}{20}\)

\(\Rightarrow x=\frac{19}{20}\)

Vậy \(x=\frac{19}{20}\)

~ Ủng hộ nhé 

\(x+\frac{12}{15}=\frac{7}{5}\)

\(\Rightarrow x=\frac{7}{5}-\frac{12}{15}\)

\(\Rightarrow x=\frac{7}{5}-\frac{4}{5}\)

\(\Rightarrow x=\frac{3}{5}\)

c ) 

\(x:\frac{17}{25}=\frac{15}{34}\)

\(\Rightarrow x=\frac{15}{34}\times\frac{17}{25}\)

\(\Rightarrow x=\frac{3}{10}\)

Vậy \(x=\frac{3}{10}\)

d ) 

\(\frac{1}{5}\times x=\frac{9}{45}\)

\(\Rightarrow x=\frac{9}{45}:\frac{1}{5}\)

\(\Rightarrow x=\frac{9}{45}\times5\)

\(\Rightarrow x=\frac{9}{5}\)

Vậy \(x=\frac{9}{5}\)

~ Ủng hộ nhé 

a =143

b = 2510

c 28 x 73 = 2044

cái câu c tính nhẩm chết liền

d [ 1700 - 340 +17 ] : 17 = 81

2 . Tìm x 

a 7 . [ x - 3 ] - 6 = 1

   7 . [ x - 3 ]   = 1+6

7 . [ x - 3 ]     = 7

     x - 3 = 7 : 7

x - 3 =1

x=3+1=4

b 

[x+5] .2:11=6

[x+5] x 2  = 6 x 11

[ x + 5 ] x 2 = 66

x+2=66:2

x+2=33

x=33-2=31

Bài 1 

a, \(45+98=143\)

b, \(2605-95=2510\)

c,\(28.73+28\)

\(=28.\left(73+1\right)\)

\(=28.74\)

\(=2072\)

d,\(\left[1700-340+17\right]:17\)

\(=1700:17-340:17+17:17\)

\(=100-20+1\)

\(=81\)

Bài 2 

a, \(7.\left(x-3\right)-6=1\)

\(\Leftrightarrow7.\left(x-3\right)=7\)

\(\Leftrightarrow x-3=1\)

\(\Leftrightarrow x=4\)

b, \(\left(x+2\right).2:11=6\)

\(\Leftrightarrow\left(x+2\right).2=66\)

\(\Leftrightarrow x+2=33\)

\(\Leftrightarrow x=31\)

a) x+(-45)=(-62)+17

=>x-45=-45

=>x=-45+45

=>x=0

b) x+29=/-43/+(-43)

=>x+29=43-43

=>x+29=0

=>x=-29

c) 5+/x+1/=29

=>/x+1/=29-5=24 

\(\orbr{\begin{cases}x+1=24\\x+1=-24\end{cases}}\Rightarrow\orbr{\begin{cases}x=23\\x=-25\end{cases}}\)

P/s tham khảo bài mình nha

a ) x + (-45) =-45

     = > x = 0

b ) x + 29 = 0

=> x = -29

c ) => /x+1/ = 29-5

/x+1/ = 24 

=> x+1 = + - 24 

TH1 : x+1=24

=> x =23

th2 : x+1 = -24

=> x =-25

vậy x thuộc { 23 ; -25}

323400 nha !

A = 1.2 + 2.3 + 3.4 + ... + 98.99 

3A = 1.2.3 + 2.3.3 + 3.4.3 + ...+ 98.99.3

3A = 1.2.3 + 2.3.(4 -1) + 3.4.(5 - 2) + ...+ 98.99.(100 - 97)

3A = (1.2.3 + 2.3.4 + 3.4.5 + ... + 98.99.100) - (0.1.2 + 1.2.3  + 2.3.4 + ... + 97.98.99)

3A = 1.2.3 + 2.3.4 + 3.4.5 + ... + 98.99.100 

3A = 98.99.100

=> A = \(\frac{98.99.100}{3}=323400\)