3^x=3^2x3^2

3^x=3^4

Suy ra x =4

Giải 1 phần thui mệt was

a) 3^x = 3² . 9

3^x = 3² . 3²

3^x = 3⁴

=> x = 4

b) ( 21 + x ) : 9 = 9⁵ : 9⁴

(21 + x ) : 9 = 9

21 + x  = 9 . 9

21 + x = 81

x = 81 - 21

x = 60

c) 5^x + 1 - 13 = 613

5^x = 613 + 13 - 1

5^x = 625

5^x = 5⁴

=> x = 4

a)\(3^x=3^{^{ }}^2.9\)

\(3^x=3^2.3^2\)

\(3^x=3^{2+2}=3^4\)

\(\Rightarrow x=4\)

b)\(\left(21+x_{ }\right):9=9^5:9^4\)

\(\left(21+x\right):9=9^{5-4}=9\)

\(21+x=9.9\)

\(x=81-21=60\)

c)\(5^x-1-13=613\)

\(5^x-\left(1+13\right)=613\)

\(5^x=613+14=625\)

\(5x=5^4\)

\(\Rightarrow x=4\)

Tìm x thuoc z:

1) \(26-\left|x+9\right|=-13\)

\(\Leftrightarrow\left|x+9\right|=26-\left(-13\right)\)

\(\Leftrightarrow\left|x+9\right|=39\)

\(\Leftrightarrow\left[{}\begin{matrix}x+9=39\\x+9=-39\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=39-9=30\\x=-39-9=-48\end{matrix}\right.\)

Vậy: \(x\in\left\{30;-48\right\}\)

2) \(\left|x+7\right|-13=25\)

\(\Leftrightarrow\left|x+7\right|=25+13=38\)

\(\Leftrightarrow x+7\in\left\{38;-38\right\}\)

\(\Leftrightarrow x\in\left\{31;-45\right\}\)

Vậy:.................

tim x biet

\(1)123-3.\left(x+4\right)=23\)

\(\Leftrightarrow3\left(x+4\right)=123-23\)

\(\Leftrightarrow3\left(x+4\right)=100\)

\(\Leftrightarrow x+4=\frac{100}{3}\)

\(\Leftrightarrow x=\frac{100}{3}-4=\frac{100-12}{3}=\frac{88}{3}\)

Vậy:................

2) Tương tự

a) 17.13+17.42-17.35

=17.(13+42-35)

=17.20=340

b) [25.(18-4²)-10]:4+6

=(25.2-10):4+6

=40:4+6=16

c) 3⁶:3²+2³.2²-3².3

=3⁴+2⁵-3³

=81+32-27=86

d) B=3.4²-2².3

=3.(16-4)

=3.12=36

e)2022⁰+3.[5².10-(23-13)²]

=1+3.(250-100)

=1+450=451

g) 27.77+24.27-27

=27.(77+24-1)

=27.100=2700

h) 5.2³+7⁹:7⁷-1²⁰²⁰

=40+7²-1

=89-1=88

i) 120:{54[50:2+(3²-2.4)]}

=120:[54(25+1)]

=120:1404=10/117

\(\frac{5}{7}+\frac{3}{4}=\frac{41}{28}\)\(Đ\)

\(3+\frac{2}{5}=1\)\(S\)

\(\frac{11}{9}-\frac{5}{6}=\frac{7}{18}\)\(Đ\)

\(4-\frac{3}{7}=\frac{25}{7}\)\(Đ\)

\(x+\frac{4}{11}=\frac{3}{5}\).

          \(x=\frac{3}{5}-\frac{4}{11}\)

          \(x=\frac{13}{55}\)

Vậy ta chọn câu C

dung hay sai

5/7 + 3/4 = 41/28 .....Đ...

3 + 2/5 = 1....S....

11/9 - 5/6 = 7/18....Đ...

4 - 3/7 = 25/7.....

tim x

x + 4/11 =3/5

Đáp án : C .13/55

Bài Đúng hay Sai :

5/7 + 3/4 = 41/28 là đúng 

3 + 2/5 = 1 là sai 

11/9 - 5/6 = 7/18 là đúng 

4 - 3/7 = 25/7 là đúng 

Bài tìm x :

x + 4/11 = 3/5 

           x  = 3/5 - 4/11 

           x  = 13/55 

Vậy chọn đáp án C .

~ Chúc em học giỏi ! ~

Ta có

         1 = 0 + 1;

         5 = 2 + 3;

         9 = 4 + 5;

         ....

         x = a + ( a + 1 )

         => 1 + 5 + 9 + 13 + 17 + ... + x = 501

              = 1 + 2 + 3 + 4 + 5 + 6 + 7 + ... + a + ( a + 1 ) = 506

              Hay [ ( a - 1 ) - 1 ]  x ( a - 1) 2 [ ( a - 1 ) - 1 ] x ( a - 1 ) 2 = 506

              => ( a + 1 ) x ( a + 2 ) = 506

              => a = 21

Do đó x = 21 + 21 + 1 = 43

Ta có

         1 = 0 + 1;

         5 = 2 + 3;

         9 = 4 + 5;

         ....

         x = a + ( a + 1 )

         => 1 + 5 + 9 + 13 + 17 + ... + x = 501

              = 1 + 2 + 3 + 4 + 5 + 6 + 7 + ... + a + ( a + 1 ) = 506

              Hay [ ( a - 1 ) - 1 ]  x ( a - 1) 2 [ ( a - 1 ) - 1 ] x ( a - 1 ) 2 = 506

              => ( a + 1 ) x ( a + 2 ) = 506

              => a = 21

Do đó x = 21 + 21 + 1 = 43

(x+1)x:2=501.1001. =>(x+1)x=1002.1001=>x=1001

​

​

Ta co :

x+1:4+1=501501

x+1:4    = 501501-1

x+1:4    =501500

x+1      = 501500:4

x+1      = 125375

x         = 125375 -1

x         =125374

Vay x=125735 

**** nhe 

\(1+5+9+...+x=501501\)

\(\Leftrightarrow\frac{\left(1+x\right).\left[\left(x-1\right)\div4+1\right]}{2}=501501\)

\(\Leftrightarrow\left(1+x\right).\left[\left(x-1\right)\div4+1\right]=501501.2\)

\(\Leftrightarrow\left(1+x\right).\left[\frac{x-1}{4}+1\right]=1003002\)

\(\Leftrightarrow\frac{x-1}{4}\left(1+x\right)+x+1=1003002\)

\(\Leftrightarrow\frac{x-1}{4}+\frac{x-1}{4}x+x=1003001\)

\(\Leftrightarrow\frac{x-1+x\left(x-1\right)+4x}{4}=1003001\)

Tự giải tiếp

(x+1).x