a: \(\left(-120\right):15+12\left(2x-1\right)=52\)

=>\(12\left(2x-1\right)-8=52\)

=>\(12\left(2x-1\right)=60\)

=>\(2x-1=\dfrac{60}{12}=5\)

=>2x=5+1=6

=>\(x=\dfrac{6}{2}=3\)

c: \(x+4⋮x+1\)

=>\(x+1+3⋮x+1\)

=>\(3⋮x+1\)

=>\(x+1\in\left\{1;-1;3;-3\right\}\)

=>\(x\in\left\{0;-2;2;-4\right\}\)

d: \(2x+7⋮x+2\)

=>\(2x+4+3⋮x+2\)

=>\(3⋮x+2\)

=>\(x+2\in\left\{1;-1;3;-3\right\}\)
=>\(x\in\left\{-1;-3;1;-5\right\}\)

e: \(3x⋮x-1\)

=>\(3x-3+3⋮x-1\)

=>\(3⋮x-1\)

=>\(x-1\in\left\{1;-1;3;-3\right\}\)

=>\(x\in\left\{2;0;4;-2\right\}\)

a) Ta có: \(\left(-12\right)-\left|13-x\right|=-21\)

\(\Leftrightarrow-\left|x-13\right|-12=-21\)

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

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

\(\Leftrightarrow\left[{}\begin{matrix}x-13=9\\x-13=-9\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=22\\x=4\end{matrix}\right.\)

Vậy: \(x\in\left\{22;4\right\}\)

b) Ta có: \(8\le\left|x\right|< 9\)

\(\Leftrightarrow\left|x\right|=8\)

\(\Leftrightarrow x\in\left\{8;-8\right\}\)

Vậy: \(x\in\left\{8;-8\right\}\)

c) Ta có: \(x-\left(-25+x\right)=13-x\)

\(\Leftrightarrow x+25-x-13+x=0\)

\(\Leftrightarrow x+12=0\)

hay x=-12

Vậy: x=-12

d) Ta có: \(\left(15-30\right)+x=x-\left(27-\left|-8\right|\right)\)

\(\Leftrightarrow x-15=x-\left(27-8\right)\)

\(\Leftrightarrow x-15-x+19=0\)

\(\Leftrightarrow-4=0\)(vô lý)

Vậy: \(x\in\varnothing\)

\(a,\Leftrightarrow x^3=\dfrac{20}{3}\Leftrightarrow x=\sqrt[3]{\dfrac{20}{3}}\\ b,\Leftrightarrow x-1=9\Leftrightarrow x=10\\ c,\Leftrightarrow\left[{}\begin{matrix}x-1=5\\x-1=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-4\end{matrix}\right.\\ d,\Leftrightarrow2x+1=5\Leftrightarrow x=2\\ e,\Leftrightarrow2x-4=4\Leftrightarrow x=4\)

Câu a) xem lại đề giùm nhé em

b) \(\left(x-1\right)^3=9^3\)

\(x-1=9\)

\(x=10\)

Vậy \(x=10\)

c) \(\left(x-1\right)^2=25\)

\(x-1=5\) hoặc \(x-1=-5\)

* \(x-1=5\)

\(x=6\)

* \(x-1=-5\)

\(x=-4\)

Vậy \(x=-4\); \(x=6\)

d) \(\left(2x+1\right)^3=125\)

\(\left(2x+1\right)^3=5^3\)

\(2x+1=5\)

\(2x=4\)

\(x=2\)

Vậy \(x=2\)

e) Sửa đề: \(\left(2x+4\right)^3=64\)

\(\left(2x+4\right)^3=4^3\)

\(2x+4=4\)

\(2x=0\)

\(x=0\)

Vậy \(x=0\)

a: \(3x\left(x-3\right)+4x-12=0\)

=>\(3x\left(x-3\right)+\left(4x-12\right)=0\)

=>\(3x\left(x-3\right)+4\left(x-3\right)=0\)

=>\(\left(x-3\right)\left(3x+4\right)=0\)

=>\(\left[{}\begin{matrix}x-3=0\\3x+4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-\dfrac{4}{3}\end{matrix}\right.\)

b: Sửa đề:\(\left(x+1\right)\left(x^2-x+1\right)-x^3+2x=17\)

\(\Leftrightarrow x^3+1-x^3+2x=17\)

=>2x+1=17

=>2x=17-1=16

=>\(x=\dfrac{16}{2}=8\)

c: \(\left(x-3\right)\left(x+5\right)+\left(x-1\right)^2-6x^4y^2:3x^2y^2=15x\)

=>\(x^2+2x-15+x^2-2x+1-2x^2=15x\)

=>\(15x=-14\)

=>\(x=-\dfrac{14}{15}\)

a. 8 x 37 x 5 x 25 = (8 x 25) x 37 x 5

                             = 200 x 5 x 37 = 1000 x 37 = 37000

b. 48 x 34 + 6 x 66 x 8 = 48 x 34 + 48 x 66 = 48 x ( 34 + 66) = 48 x 100 = 4800

c. 17 x (13 - 5) + 17 x 5 = 17 x 8 + 17 x 5 = 17 x (8 + 5) = 17 x 13 = 221

d. 78 x 100 - 100 = 78 x 100 - 100 x 1 = 100(78 - 1) = 100 x 77 = 7700

e. 6 x 17 x 8 + 3 x 37 x 16 + 4 x 46 x 12

= 48 x 17 + 48 x 37 + 48 x 46

= 48 x (17 + 37 + 46)

= 48 x 100 = 4800

f. 47 x 43 + 47 x 73 - 8 x 47 x 2 = 47 x 43 + 47 x 73 - 47 x 16 = 47 x (43 + 73 - 16) = 47 x 100 = 4700

8×37×5×25=296×5×25=1480×25=37000

48×34+6×66×8=1632+396×8=1632+3168=4800

15×(13-7)+17×5=15×6+17×5=90+85=175

78×100-100=7800-100=7700

a)\(\dfrac{24}{36}\)=\(\dfrac{8}{12}\)

b)\(\dfrac{14}{56}\)=\(\dfrac{1}{4}\)

c)\(\dfrac{9}{24}\)=\(\dfrac{21}{56}\)

Chúc bạn học tốt!

a: x/12=24/36

nên x/12=2/3

=>x=2/3x12=8

b: 1/x=14/56

nên 1/x=1/14

hay x=14

c: x/56=9/24

=>x/56=3/8

hay x=21