Bài 1 : a ) 

| 2x + 3 | = 5 

  2x          = 5 - 3 

  2x          = 2 

    x          = 2 : 2 

    x          = 1 

Cảm ơn bạn nhìu !

Bài 1 : 

A ) 3 < x < 5

=> x thuộc  { 4 }

Vậy x = 4

Câu b và câu c cứ theo vậy mà làm .

Bài 2 : 

| x + 7 | = 0 

  x         = 0 - 7 

  x         = -7

Vậy x = -7

Bài 1:

a, 3<x<5 => x=4

b, -4 < x - 1 < 5

=> x-1 thuộc {-3;-2;-1;0;1;2;3;4}

=> x thuộc {-2;-1;0;1;2;3;4;5}

c, -8 < x+2 < -3

=> x+2 thuộc {-7;-6;-5;-4}

=> x thuộc {-9;-8;-7;-6}

Bài 2L

a, |x+7|=0

=>x+7=0

=>x=-7

b,|x+10|=x+10

TH1: x+10=x+10

=> 0 = 0 (loại)

TH2: x + 10 = -x-10

=> -2x = 20

=> x = -10

Vậy x=-10

c, TH1: x - 15 = 15 - x

=> 2x = 30

=> x = 15

TH2: x - 15 = x - 15 

=> 0 = 0 (loại)

Vậy x=15

d, (x-3)(x+2)=0

\(\Rightarrow\orbr{\begin{cases}x-3=0\\x+2=0\end{cases}\Rightarrow\orbr{\begin{cases}x=3\\x=-2\end{cases}}}\)

\(a)\)\(\left[\left(8.x-12\right)\div4\right].3^3=3^6\)

\(\left[\left(8.x-12\right)\div4\right]=3^6\div3^3\)

\(\left[\left(8.x-12\right)\div4\right]=3^3\)

\(\left(8.x-12\right)\div4=27\)

\(\left(8.x-12\right)=27.4\)

\(8.x-12=108\)

\(8.x=108+12\)

\(8.x=120\)

\(x=120\div8\)

\(x=15\)

\(b)\)\(3^{2.x-4}-x^0=8\)

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

\(3^{2.x-4}=8+1\)

\(3^{2.x-4}=9\)

\(3^{2.x-4}=3^2\)

\(2.x-4=2\)

\(2.x=2+4\)

\(2.x=6\)

\(x=3\)

Sửa đề

\(c)\)\(65-4^{x+2}=2014^0\)

\(65-4^{x+2}=1\)

\(4^{x+2}=65-1\)

\(4^{x+2}=64\)

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

\(x+2=3\)

\(x=3-2\)

\(x=1\)

i) 58:252=58:(52)2=58:52.2=58:54=58−4=54

k) 49:642=49:(43)2=49:43.2=49:46=49−6=43

l) 225:324=225:(25)4=225:25.4=225:220=225−20=25

m) 1253:254=(53)3:(52)4=53.3:52.4=59:58=5

e) 38:36=38−6=32

f)  210:83=210:(23)3=210:23.3=210:29=210−9=2

g) 127:67=(12:6)7=27

h_ 215:813kết quả là số dư nên không tính ( đề sai )

a) 410.230=(22)10.230=22.10.230=220.230=220+30=250

b) 925.274.813=(32)25.(33)4.(34)3=33.25.33.4.34.3=375.312.312=375+12+12=399

c) 2550.1255=(52)50.(53)5=52.50.53.5=5100.515=5100+15=5115

d) 643.48.164=(43)3.48.(42)4=43.3.48.42.4=49.48.48=49+8+8=425

mk ko btttttttttt

\(A=\left(x-\dfrac{1}{5}\right)^2+\dfrac{11}{12}\ge\dfrac{11}{12}\forall x\)

Dấu '=' xảy ra khi \(x=\dfrac{1}{5}\)

a) \(\frac{10^4.81-16.15^2}{\left(-8\right)^4.3^{12}+6^{11}}=\frac{10^4.3^4-4^2.15^2}{8^4.3^{12}+6^{11}}=\frac{30^4-60^2}{2^{12}.3^{12}+6^{11}}=\frac{\left(30^2\right)^2-60^2}{6^{12}+6^{11}}\)

\(=\frac{900^2-60^2}{6^{11}.\left(6+1\right)}=\frac{60^2.\left(15^2-1\right)}{6^{11}.7}=\frac{60^2.224}{6^{11}.7}=\frac{2^9.3^2.5^2.7}{2^{11}.3^{11}.7}=\frac{5^2}{2^2.3^9}=\frac{25}{78732}\)

180 nha

a) Ta có: 12⁸ .9¹² 

= (3.2 )² .(3² )¹²

= 3⁸ .2¹⁶ .3²⁴

= 2¹⁶ .3³²

= 2¹⁶ . (3²)¹⁶ 

= 2¹⁶ .9¹⁶

= 18¹⁶ (đpcm)

b) Ta có: 45¹⁰ .5³⁰

= (5.3² )¹⁰ .5³⁰

= 5¹⁰ .3²⁰ .5³⁰

= 5⁴⁰ .3²⁰

= (5² )²⁰ .3²⁰

= 25²⁰ .3²⁰

= 75²⁰ (đpcm) 

n sẽ bằng -16 chuc ban manh khoe

\(x^2-6^2=8^2\)

\(\Rightarrow\left(x-6\right)\left(x+6\right)=8^2\)

\(\Rightarrow\left(x-6\right)\left(x+6\right)=64\)

x²-6²=8²

=>x²-36=64

=>x²=64+36=100

=>x=+10 và -10

vậy ..................>_<