a) => x-20=11

         x-20= -11

=> x= 31

     x= 9

tick nha kim thu quynh

a)|x-20|=11

=>x-20=11  hoặc x-20=-11

x=11+20             x=-11+20

x=31                   x=9

\(\left(x-1\right)^3=125\)

\(\left(x-1\right)^3=5^3\)

\(\Rightarrow x-1=5\)

\(\Rightarrow x=6\)

cach lam nhu vay do ban

(x - 1)³ = 125

(x - 1)³ = 5³

x - 1 = 5

x      = 5 + 1 

x       =   6

Vậy x = 6

7 (x-3)=3x-1

7x -21=3x -1

7x +3x =-1 +21

10x=20

x=20:10=2

Thank bn vì lời chúc, bn cute thiệt ó ^^!

a,

x+(x+1)+(x+2)+...+(x+100)=100x+6000

x+x+x+...+x +(1+2+3+...+100)= 100x+6000

101x+(1+100)+(2+99)+...+(50+52)=100x+6000

101x+101+101+...101=100x+6000

101x+101.50=100x+6000

101x+5050=100x+6000

100x+x+5050=100x+6000

từ đây ta suy ra :

x+5050=6000

x=6000-5050

x=50

4^x + 4³ + 4^x= 1040

4^x  . ( 4³ + 1 ) = 1040

4^x . 65 = 1040

4^x = 1040 : 65 

4^x = 16

4 ^x = 4²

suy ra x = 2

vậy x = 2

bài này tìm x nhé mình quên ghi

(6^{2007 -} 6²⁰⁰⁶):6²⁰⁰⁶ =6²⁰⁰⁷:6²⁰⁰⁶-6²⁰⁰⁶:6²⁰⁰⁶=6-1=5

\(\left(6^{2007}-6^{2006}\right):6^{2006}\)

\(=6^{2007}:6^{2006}-6^{2006}:6^{2006}\)

\(=6^{2007-2006}-1\)

\(=6^1-1\)

\(=6-1\)

\(=5\)

\(\left(7^3+7^5\right).\left(5^4+5^6\right).\left(3^3.3-9^2\right)\)

\(=\left(7^3+7^5\right).\left(5^4+5^6\right).\left(3^{3+1}-9^2\right)\)

\(=\left(7^3+7^5\right).\left(5^4+5^6\right).\left(3^4.9^2\right)\)

\(=\left(7^3+7^5\right).\left(5^4+5^6\right).\left[3^4-\left(3^2\right)^2\right]\)

\(=\left(7^3+7^5\right).\left(5^4+5^6\right).\left(3^4-3^4\right)\)

\(=\left(7^3+7^5\right).\left(5^4+5^6\right).0\)

\(=0\)

tinh tong cua 11,10,9,8,7,6,5,..........,-37,-38

-675 nha ban