\(3^{x+4}+3^{x+2}=270\Rightarrow3^{x+2}\left(3^2+1\right)\)\(=270\Rightarrow3^{x+2}\cdot10=270\)\(=>3^{x+2}=270:10=27=>x=1\)

(2x-5)⁵ = 3¹⁰

=> 2x-5 = 3²=9

=> 2x = 14

=> x = 7

(190-2x):25=270

190-2x       =270.25

190-2x       =6750

      2x       =6750-190

      2x       =    6560

       x        = 6560/2=3280

720:[41-(2x-5)]=2^3.5

720:[41-(2x-5)]=40

       41-(2x-5)=720/40

       41-(2x-5)=   18

            2x-5 = 41-18

            2x-5 =   23

            2x    =   23+5

            2x    =     28

             x     = 28/2=14

Còn bài 3 thì mình chịu

a)\(280-\left(x-140\right):35=270\)

\(\Leftrightarrow\left(x-140\right):35=10\)

\(\Leftrightarrow x-140=350\)

\(\Leftrightarrow x=490\)

b) \(\left(190-2x\right):35-32=16\)

\(\Leftrightarrow\left(190-2x\right):35=48\)

\(\Leftrightarrow190-2x=1680\)

\(\Leftrightarrow2x=-1490\Leftrightarrow x=-745\)

c) \(720:\left[41-\left(2x-5\right)\right]=2^3.5\)

\(\Leftrightarrow720:\left[41-\left(2x-5\right)\right]=40\)

\(\Leftrightarrow41-\left(2x-5\right)=18\)

\(\Leftrightarrow2x-5=23\)

\(\Leftrightarrow2x=28\Leftrightarrow x=14\)

280-(x-140):35=270

(x-140):35=280-270

(x-140):35=10

(x-140)=10×35

(x-140)=350

x=350-140

x=210

vậy x=210

(192-2x):35-32=16

(192-2x):35=16+32

(192-2x):35=48

(192-2x)=48×35

(192-2x)=1680

2x=192-1680

2x=-1488

x=-1488:2

x=-744

vậy x=-744

a, 7\(x\) - \(x\) = 5²¹ : 5¹⁹ + 3.2².7

     6\(x\)    = 5³ + 3.4.7

    6\(x\)    = 125 + 12.7

    6\(x\)  = 125 + 84

    6\(x\) = 209

     \(x\)  = 209 : 6

    \(x\) = \(\dfrac{209}{6}\)

b; 11\(x\) - 7\(x\) + 3⁴ : 3³ = 5⁴ + 2\(x\)

    4\(x\) + 3 = 625 + 2\(x\)

   4\(x\) - 2\(x\) = 625 - 3

   2\(x\)        = 622

     \(x\)        = 622 : 2

    \(x\)        = 311

c; 75 - 5.(\(x-3\))³ = 700

          5.(\(x\) - 3)³ = 700 - 75

         5.(\(x\) - 3)³ = - 625

           (\(x\) - 30)³ = - 625 : 5

           (\(x\) - 30)³ = - 125

           (\(x-3\))³ =  (-5)³

           \(x\) - 3 = - 5 

           \(x\)         = - 5 + 3

            \(x\)       = -2

d, 3.(2\(x\) - 1)² = 75

       (2\(x\) - 1)² = 75 : 3

       (2\(x\) - 1)² = 25

       \(\left[{}\begin{matrix}2x-1=-5\\2x-1=5\end{matrix}\right.\)

       \(\left[{}\begin{matrix}2x=-5+1\\2x=5+1\end{matrix}\right.\)

       \(\left[{}\begin{matrix}2x=-4\\2x=6\end{matrix}\right.\)

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

a: \(280-\left(x-140\right):35=270\)

=>(x-140):35=280-270=10

=>x-140=350

=>x=350+140

=>x=490

b: \(\left(190-2x\right):35-32=16\)

=>\(\left(190-2x\right):35=32+16=48\)

=>\(190-2x=35\cdot48=1680\)

=>2x=190-1680=-1490

=>x=-745

c: \(720:\left\lbrack41-\left(2x-5\right)\right\rbrack=2^3\cdot5\)

=>\(720:\left\lbrack41-\left(2x-5\right)\right\rbrack=8\cdot5=40\)

=>41-(2x-5)=720:40=18

=>2x-5=41-18=23

=>2x=28

=>x=14

d: \(\left(x:23+45\right)\cdot37-22=2^4\cdot105\)

=>\(\left(\frac{x}{23}+45\right)\cdot37=16\cdot105+22=1702\)

=>\(\frac{x}{23}+45=46\)

=>\(\frac{x}{23}=1\)

=>x=23

e: \(\left(3x-4\right)\left(x-1\right)^3=0\)

=>\(\left[\begin{array}{l}3x-4=0\\ x-1=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac43\\ x=1\end{array}\right.\)

f: \(2^{2x-1}:4=8^3\)

=>\(2^{2x-1-2}=2^9\)

=>2x-3=9

=>2x=12

=>x=6

g: \(x^{17}=x\)

=>\(x^{17}-x=0\)

=>\(x\left(x^{16}-1\right)=0\)

=>\(\left[\begin{array}{l}x=0\\ x^{16}-1=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x^{16}=1\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x=1\\ x=-1\end{array}\right.\)

h: \(\left(x-5\right)^4=\left(x-5\right)^6\)

=>\(\left(x-5\right)^6-\left(x-5\right)^4=0\)

=>\(\left(x-5\right)^4\cdot\left\lbrack\left(x-5\right)^2-1\right\rbrack=0\)

=>\(\left(x-5\right)^4\cdot\left(x-4\right)\left(x-6\right)=0\)

=>x∈{4;5;6}

i: \(\left(x+2\right)^5=2^{10}\)

=>\(\left(x+2\right)^5=\left(2^2\right)^5=4^5\)

=>x+2=4

=>x=2

k: 1+2+3+...+x=78

=>\(\frac{x\left(x+1\right)}{2}=78\)

=>x(x+1)=156

=>\(x^2+x-156=0\)

=>(x+13)(x-12)=0

=>x=-13(loại) hoặc x=12(nhận)

l: \(\left(3x-2^4\right)\cdot7^3=2\cdot7^4\)

=>\(3x-16=2\cdot\frac{7^4}{7^3}=2\cdot7=14\)

=>3x=16+14=30

=>\(x=\frac{30}{3}=10\)

n: \(5^{x}:5^2=125\)

=>\(5^{x-2}=5^3\)

=>x-2=3

=>x=5

m: \(\left(x+1\right)^2=\left(x+1\right)^0\)

=>\(\left(x+1\right)^2=1\)

=>\(\left[\begin{array}{l}x+1=1\\ x+1=-1\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0\\ x=-2\end{array}\right.\)

o: Số số hạng của dãy số 2;4;..;52 là:

(52-2):2+1=50:2+1=25+1=26(số)

Tổng của dãy số 2;4;...;52 là:

\(\left(52+2\right)\cdot\frac{26}{2}=54\cdot13=702\)

(2+x)+(4+x)+...+(52+x)=780

=>26x+702=780

=>26x=78

=>x=3

p: \(70=2\cdot5\cdot7;80=2^4\cdot5\)

=>ƯCLN(70;80)=\(2\cdot5=10\)

70⋮x; 80⋮x

=>x∈ƯC(70;80)

=>x∈Ư(10)

mà x>8

nên x=10

q: \(12=2^2\cdot3;25=5^2;30=2\cdot3\cdot5\)

=>BCNN(12;25;30)=\(2^2\cdot3\cdot5^2=300\)

x⋮12; x⋮25; x⋮30

=>x∈BC(12;25;30)

=>x∈B(300)

mà 0<x<500

nên x=300

\(257-\left(3x+25\right)=157\)

\(3x+25=257-157\)

\(3x+25=100\)

\(3x=75\)

\(x=25\)

vay \(x=25\)

\(x-140:35=270\)

\(x-4=270\)

\(x=274\)

vay \(x=274\)

\(23-\left(x:13\right)=18\)

\(\frac{x}{13}=5\)

\(\frac{x}{13}=\frac{65}{13}\)

\(\Rightarrow x=65\)

vay \(x=65\)

\(9\left(x+5\right)-13=671\)

\(9x+45=684\)

\(9x=639\)

\(x=71\)

vay \(x=71\)

\(9\left(4x\right)-13=24\)

\(36x=37\)

\(x=\frac{37}{36}\)

vay \(x=\frac{37}{36}\)

\(\left(x-5\right)-34:17=1\)

\(\left(x-5\right)-2=1\)

\(x-5=3\)

\(x=8\)

vay \(x=8\)

\(\left(2x-7\right).3=3\)

\(2x-7=1\)

\(2x=8\)

\(x=4\)

vay \(x=4\)

\(\left(3x-5\right):2=4.5\)

\(\left(3x-5\right):2=20\)

\(3x-5=10\)

\(3x=15\)

\(x=5\)

vay \(x=5\)

con lai lam tuong tu 

mk moi tay roi nen ban tu lam vay

bạn làm tiếp thì mk đánh 2 tích nữa 

a.\(2^x-2^4.2^7.32=0\)
\(2^x-2^{16}=0\)
\(=>x=16\)
b.\(3^x+3^{x+2}=270\)
\(3^x+3^x.3^2=270\)
\(3^x.10=270\)
\(3^x=27\)
\(=>x=3\)
 

bạn ơi giải chi tiết đi đừng gộp

1)  280-(x-140):35=270  

=> (x-140):35=10

=> x-140=350

=>x=490

2) 720:[41-(2x-5)]=2³.5 

=>720:[41-(2x-5)]=40

=>41-(2x-5)=18

=>2x-5=23

=>2x=28

=>x=14

3) (3x-4).(x-1)³=0       

=>3x-4=0 hoặc (x-1)³=0

• Với 3x-4=0 <=>x=\(\frac{4}{3}\)
• Với (x-1)³=0 <=>x=0

4) x¹⁷=x

=>x¹⁷-x=0

=>x(x¹⁶-1)=0

=>x=0 hoặc x¹⁶-1=0

• Với x=0
• Với x¹⁶-1=0 =>x=-1 hoặc 1

5) 5^x:5²=125

=>5^x-2=125

=>5^x-2=5³

=>x-2=3

=>x=5

6)(x+2)⁵=2¹⁰

=>(x+2)⁵=1024

=>(x+2)⁵=4⁵

=>x+2=4

=>x=2

do đề ra cm .... nên chắc chắc điều đó đúng ok