siuu

a: \(\left|x\right|-\dfrac{38}{7}\left|x\right|-\dfrac{3}{4}=2\left|x\right|-\dfrac{8}{7}\)

\(\Leftrightarrow\left|x\right|\cdot\dfrac{-45}{7}=-\dfrac{8}{7}+\dfrac{3}{4}=\dfrac{-32+21}{28}=\dfrac{-11}{28}\)

=>|x|=11/180

=>x=11/180 hoặc x=-11/180

b: \(\Leftrightarrow x\cdot\dfrac{13}{4}-\dfrac{7}{6}x=\dfrac{5}{12}+\dfrac{5}{3}\)

=>25/12x=25/12

hay x=1

\(\dfrac{93}{17}:x+\left[\dfrac{-4}{17}\right]:x+\dfrac{22}{7}:\dfrac{52}{3}=\dfrac{4}{11}\)

\(=>\left(\dfrac{93}{17}+\dfrac{-4}{17}\right):x+\dfrac{11}{26}=\dfrac{4}{11}\)

\(=>\dfrac{89}{17}:x+\dfrac{11}{26}=\dfrac{4}{11}\)

\(=>\dfrac{89}{17}:x=\dfrac{4}{11}-\dfrac{11}{26}\)

\(=>\dfrac{89}{17}:x=\dfrac{-17}{286}\)

\(=>x=\dfrac{89}{17}:\dfrac{-17}{286}\)

\(=>x=\dfrac{-25454}{289}=-88\dfrac{22}{289}\)

\(\dfrac{93}{17}:x-\dfrac{4}{17}:x+\dfrac{22}{7}:\dfrac{52}{3}=\dfrac{4}{11}\)

\(\Rightarrow\left(\dfrac{93}{17}-\dfrac{4}{17}\right):x+\dfrac{33}{182}=\dfrac{4}{11}\)

\(\Rightarrow\dfrac{89}{17}:x=\dfrac{365}{2002}\)

\(\Rightarrow x=\dfrac{178178}{6205}\)

Ta có: \(\dfrac{93}{17}:x+\dfrac{-4}{17}:x+\dfrac{22}{7}:\dfrac{52}{3}=\dfrac{4}{11}\)

\(\Leftrightarrow\dfrac{89}{17}:x=\dfrac{365}{2002}\)

hay \(x=\dfrac{178178}{6205}\)

a: \(61\cdot45+61\cdot23-68\cdot51\)

\(=61\left(45+23\right)-68\cdot51\)

\(=68\cdot61-68\cdot51\)

\(=68\left(61-51\right)=68\cdot10=680\)

b: \(3\cdot5^2-\left(75-4\cdot2^3\right)\)

\(=75-75+4\cdot8\)

\(=4\cdot8=32\)

c: \(36:\left\{2^2\cdot5-\left[30-\left(5-1\right)^2\right]\right\}\)

\(=\dfrac{36}{20-30+4^2}\)

\(=\dfrac{36}{-10+16}=\dfrac{36}{6}=6\)

d: \(\left(12\cdot49-3\cdot2^2\cdot7^2\right):\left(2020\cdot2021\right)\)

\(=\dfrac{\left(12\cdot49-12\cdot49\right)}{2020\cdot2021}=0\)

(93/17+-4/17) : x + 33/182=4/11

89/17 : x = 4/11 + 33/182

89/17 : x = Sia đề

\(\Rightarrow16-3x=504:72=7\\ \Rightarrow3x=16-7=9\Rightarrow x=3\\ \left(2^2\cdot x-5^2\right)\cdot3^8=3^9\\ \Rightarrow4x-25=3^9:3^8=3\\ \Rightarrow4x=28\Rightarrow x=7\)

504 : (16 - 3x) = 72 (ĐK: \(x\ne\dfrac{16}{3}\))

<=> 16 - 3x = 504 : 72

<=> 16 - 3x = 7

<=> 16 - 7 = 3x

<=> 3x = 9

<=> x = 3 (tM)

(2²x - 5²) . 3⁸ = 3⁹

<=> (4x - 25) . 6561 = 19683

<=> 4x - 25 = 19683 : 6561

<=> 4x - 25 = 3

<=> 4x = 3 + 25

<=> 4x = 28

<=> x = 7 

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.

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

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

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

$2x=28+6=34$

$x=34:2=17$

a: \(ƯCLN=25\)

\(BCNN=5^2\cdot3\cdot7=525\)

b: \(ƯCLN=15\)

\(BCNN=3\cdot5\cdot11\cdot7\cdot2^2=9240\)

a) ƯCLN: 25

BCNN: 525

b) ƯCLN: 15

BCNN: 4620