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Bài 2:

a. $=58(75+50-25)=58.100=5800$
b. $=27.8+4.9-5=216+36-5=247$

Bài 3:

a. 

$(x-38):16=12$

$x-38=16\times 12=192$
$x=192+38 = 230$
b.

$10+2x=4^5:4^3=4^2=16$

$2x=16-10=6$

$x=6:2=3$
c.

$440+2(125-x)=546$

$2(125-x)=546-440=106$

$125-x=106:2=53$

$x=125-53=72$

d.

$(x-15):5+20=22$
$(x-15):5=22-20=2$

$x-15=2\times 5=10$

$x=10+15=25$

e.

$2x-138=2^3.3^2=8.9=72$

$2x=72+138 = 210$

$x=210:2=105$

Bài 3:

f.

$2.3^x-5=7^2$

$2.3^x=7^2+5=54$
$3^x=54:2=27=3^3$

$\Rightarrow x=3$

g.

$7x-3^3=2^7:2^4$

$7x-27=2^3=8$

$7x=27+8=35$

$x=35:7=5$
h.

$427-(x+100)=227$

$x+100=427-227 = 200$

$x=200-100=100$

i.

$2x-138=2^3.3^2=8.9=72$
$2x=72+138 = 210$

$x=210:2=105$

k.

$(6x-18):3+25.2=78$

$(2x-6)+50=78$

$2x-6=78-50=28$

$2x=28+6=34$

$x=34:2=17$

=52/78 nhe bn

26/39=

B 52/78

\(a,\Rightarrow x+2=-40\\ \Rightarrow x=-42\\ b,\Rightarrow6x-7-2x=5\\ \Rightarrow4x=12\Rightarrow x=3\\ c,\Rightarrow68-56-x=-2\\ \Rightarrow12-x=-2\\ \Rightarrow x=14\)

\(\dfrac{2^2}{1\times3}\times\dfrac{3^2}{2.4}\times\dfrac{4^2}{3.5}\times\dfrac{5^2}{4.6}=\dfrac{2^2.3^2.4^2.5^2}{1.3.2.4.3.5.4.6}=\dfrac{2^2.3^2.4^2.5^2}{1.2.3.3.4.4.5.2.3}=\dfrac{2^2.3^2.4^2.5^2}{3^3.2^2.4^2.5.1}=\dfrac{5}{3.1}=\dfrac{5}{3}\)

\(\dfrac{2^2}{1\cdot3}\cdot\dfrac{3^2}{2\cdot4}\cdot\dfrac{4^2}{3\cdot5}\cdot\dfrac{5^2}{4.6}\\ =\dfrac{2^2\cdot3^2\cdot4^2\cdot5^2}{1\cdot3\cdot2\cdot4\cdot3\cdot5\cdot4\cdot6}\\ =\dfrac{2^2\cdot3^2\cdot4^2\cdot5^2}{1\cdot2\cdot4^2\cdot4^2\cdot5\cdot6}\\ =\dfrac{2\cdot5}{6}=\dfrac{5}{3}\)

Lấy máy tính tính là ra liền : 

x = 10

mình cần giải hết ra cơ

\(\text{5*(5*x+x:5)=52*5 5*5*x+x:5*5=260 25*x+x=260 26*x=260 x=260*26 x=10 }\)

`a, 504 : (16-3x)=72`

`<=> 16-3x=7`

`<=>3x=9`

`<=>x=3`

`b,272-(4x+15)=45`

`<=>4x+15=227`

`<=>4x=212`

`<=>x=53`

a: =>16-3x=504:72=7

=>3x=9

=>x=3

b: =>4x+15=272-45=227

=>4x=212

=>x=53

a) 504 : (16 - 3\(\times\)x) = 72

=> 16 - 3\(\times\)x = 7

=> 3\(\times\)x = 9

=> x = 3

d) 272 - (4\(\times\)x + 15) = 45

=> 4\(\times\)x + 15 = 227

=> 4\(\times\)x = 212

=> x = 53

\(A=\dfrac{7^5}{7+7^2+7^3+7^4}=\dfrac{7^5}{\left(7+7^4\right)+\left(7^2+7^3\right)}=\dfrac{7^5}{7^5+7^5}=7^5\)

\(B=\dfrac{5^5}{5+5^2+5^3+5^4}=\dfrac{5^5}{\left(5+5^4\right)+\left(5^2+5^3\right)}=\dfrac{5^5}{5^5+5^5}=5^5\)

Vì 7 > 5 nên \(7^5>5^5\)

Vậy A > B

(Nhớ cho mik một tick nha cảm ơn bạn nhìu :3)