5(4x+7)=364-269

5(4x+7)=95

4x+7 = 95:5

4x+7 = 19

4x = 19-7

4x =12

x = 12:4

x = 3

`364-5 (4x+7) = 269`

`=> 5(4x+7)=364-269`

`=> 5(4x+7)=95`

`=>4x+7=95:5`

`=>4x+7=19`

`=>4x=19-7`

`=>4x=12`

`=>x=12:4`

`=>x=3`

Vậy `x=3`

\(318-5\left(x-64\right)=103\)

\(\Rightarrow5\left(x-64\right)=318-103\)

\(\Rightarrow5\left(x-64\right)=215\)

\(\Rightarrow x-64=43\)

\(\Rightarrow x=43+64\)

\(\Rightarrow x=107\)

_____________

\(4^x\cdot5+216=296\)

\(\Rightarrow4^x\cdot5=296-216\)

\(\Rightarrow4^x\cdot5-80\)

\(\Rightarrow4^x=16\)

\(\Rightarrow4^x=4^2\)

\(\Rightarrow x=2\)

___________

\(376-6^x:3=364\)

\(\Rightarrow6^x:3=376-364\)

\(\Rightarrow6^x:3=12\)

\(\Rightarrow6^x=36\)

\(\Rightarrow6^x=6^2\)

\(\Rightarrow x=2\)

___________

\(\left(4x-1\right)^2=121\)

\(\Rightarrow\left(4x-1\right)^2=11^2\)

\(\Rightarrow\left[{}\begin{matrix}4x-1=11\\4x-1=-11\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}4x=12\\4x=-10\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{5}{2}\end{matrix}\right.\)

107

2

2

TH1: 3; TH2: -5/2

a)

\(512-\left(128-5x\right)=3x+12\\ 512-128+5x=3x+12\\ 384+5x=3x+12\\ 5x-3x=12-384\\ 2x=-372\\ x=\left(-372\right):2\\ x=-186\)

b)

\(\left(2x-1\right)+\left(4x-2\right)+...+\left(400x-200\right)=5+10+...+1000\\ \left(2x+4x+...+400x\right)-\left(1+2+...+200\right)=5+10+...+1000\\ x\left(2+4+...+400\right)=\left(5+10+...+1000\right)+\left(1+2+...+200\right)\\ 2x\cdot\left(1+2+...+200\right)=5\cdot\left(1+2+...+200\right)+1\cdot\left(1+2+...+200\right)\\ 2x\cdot\left(1+2+...+200\right)=\left(5+1\right)\cdot\left(1+2+...+200\right)\\ 2x\cdot\left(1+2+...+200\right)=6\cdot\left(1+2+...+200\right)\\ \Rightarrow2x=6\\ x=6:2\\ x=3\)

c)

\(\left(x+2\right)+\left(4x+4\right)+\left(7x+6\right)+...+\left(25x+18\right)+\left(28x+20\right)=1560\\ \left(x+4x+7x+...+25x+28x\right)+\left(2+4+6+...+18+20\right)=1560\\ x\left(1+4+7+...+25+28\right)+110=1560\\ 145x+110=1560\\ 145x=1560-110\\ 145x=1450\\ x=1450:145\\ x=10\)

d)

\(x+4x+5x+9x+14x+...+97x=500\\ x\left(1+4+5+9+14+...+97\right)=500\)

Dãy số trong ngoặc có quy luật: Số thứ \(n\) bằng số thứ \(n-1\) cộng số thứ \(n-2\)

Suy ra dãy số đó là: \(1+4+5+9+14+23+37+60+97=250\)

Thế vào ta được:

\(250x=500\\ x=500:250\\ x=2\)

e)

\(720-\left[41-\left(2x-5\right)\right]=2^3\cdot5\\ 720-41+\left(2x-5\right)=8\cdot5\\ 720-41+2x-5=40\\ \left(720-41-5\right)+2x=40\\ 674+2x=40\\ 2x=40-674\\ 2x=-634\\ x=\left(-634\right):2\\ x=-317\)

f)

\(697:\dfrac{15x+364}{x}=17\\ \dfrac{15x+364}{x}=697:17\\ \dfrac{15x+364}{x}=41\\ \dfrac{15x+364}{x}\cdot x=41x\\ 15x+364=41x\\ 364=41x-15x\\ 364=26x\\ x=364:26\\ x=14\)

2/7 < 4/9

5/7 > 15/26

9/13 < 3/5

6/11 < 3/5

3/7 > 5/11

7/11 > 12/17

13/18 > 15/23

13/6 < 17/9

2/7 < 4/9

57 < 15/26

9/13 > 3/5

6/11 >3/5

7/11 < 12/17

13/18 < 15/23

13/6 < 17/9

a: 2/7=18/63

4/9=28/63

mà 18<28

nên 2/7<4/9

b: 5/7=15/21

mà 15/21>15/26

nên 5/7>15/26

c: 3/5=9/15<9/11

d: 6/11<6/10=3/5

e: 3/7=33/77

5/11=35/77

mà 33<35

nên 3/7<5/11

1,

=66

2,

=28

3,

=2016+450-2016

=450

4, 

=360-360+111

=111

5,

=1972-638-972

=1972-972-638

=362

1) = 27 + 37 + 2

= 64 + 2 = 66

2) = 6 + 26 - 4 = 32 - 4 = 28

3) = (2016-2016)+450 = 450

4) =(364-364)+111 = 111

5) = (1972-972)-638 = 1000 - 638 = 362

1. 5 + 22 + 37 + 2

= 27 + 39

= 66

2. 12 - 6 + 26 - 4

= 6 + 22

= 28

3. (2016 + 450) - 2016

= 2016 + 450 - 2016

= 2016 - 2016 + 450

= 450

4. 364 - (364 - 111)

= 364 - 364 + 111

= 0 + 111

= 111

5. 1972 - (638 + 972)

= 1972 - 638 - 972

= 1972 - 972 - 638

= 1000 - 638 

= 362

13.8.250=13.(8.250)=13.1000=13000

364-(364-111)=(364-364)+111=0+111=111

1+2+3+...+1500=(1+1500).1500:2=1125750

a, 13 x 8 x 250

= 250 x 8 x 13

=2000 x 13

=26000

còn lại tự làm nha

13 x 8 x 250 = 13 x 2 x 4 x 250 
                   = 13 x 2 x 1000 
                   = 26 x 1000
                   = 26000

 

364 + 364 + 364 + 364 + 364 + 364 + 364 + 364 + 364 + 364

= 364 x 10

= 3600

Kết quả là 3640

lấy máy tính mà bấm.

lười thế bn!!!