a, 36:(x–5) =  2 2

(x–5) = 9

x = 14

b, [3.(70–x)+5]:2 = 46

[3.(70–x)+5] = 92

70–x = 29

x = 41

c, 450:[41–(2x–5)] =  3 2 .5

41–(2x–5) = 10

2x–5 = 31

2x = 36

x = 18

d, 230+[ 2 4 +(x–5)] = 315. 2018 0

16+(x–5) = 315–230

x–5 = 85–16

x = 69+5

x = 74

e,  2 x + 2 x + 1  = 48

2 x .(2+1) = 48

2 x = 16 =  2 4

x = 4

f,  3 x + 2 + 3 x  = 2430

3 x . 3 2 + 1 = 2430

3 x = 2430:10 = 243 =  3 5

x = 5

a)  \(2x\left(x-5\right)-x\left(2x+3\right)=36\)

\(\Leftrightarrow\)\(2x^2-10x-2x^2-3x=36\)

\(\Leftrightarrow\)\(-13x=36\)

\(\Leftrightarrow\)\(x=2\)

Vậy..

b)  \(\left(3x-x+1\right)\left(x-1\right)+x^2\left(4-3x\right)=\frac{5}{2}\)

\(\Leftrightarrow\)\(2x^2-x-1+4x^2-12x^3=\frac{5}{2}\)

\(\Leftrightarrow\)\(-12x^3+6x^2-x-\frac{7}{2}=0\)

\(\Leftrightarrow\)\(24x^3-12x^2+2x+7=0\)

\(\Leftrightarrow\)\(\left(2x+1\right)\left(12x^2-12x+7\right)=0\)

\(\Leftrightarrow\)\(2x+1=0\)   ( do \(12x^2-12x+7=12\left(x-\frac{1}{2}\right)^2+4>0\))

\(\Leftrightarrow\)\(x=-\frac{1}{2}\)

Vậy...

Cả hai câu bn Giang lm sai rồi thì phải.

xin lỗi câu a mình nhầm chút nhé:

a)  \(2x\left(x-5\right)-x\left(2x+3\right)=36\)

\(\Leftrightarrow\)\(-13x=36\)

\(\Leftrightarrow\)\(x=-2\)

Vậy...

p/s: xin lỗi bạn nhé

b)3x² - 3x(x - 2)=36                         c) (3x² - x + 1)(x - 1)+ x²(4 - 3x) = 5/2

   3x² - 3x² + 6x= 36                           3x³ - 3x² - x² + x + x - 1 + 4x² - 3x³= 5/2

   6x=36 =>x=36 : 6= 6                       (3x3 - 3x3) + (-3x2 - x2 + 4x2) + (x + x) - 1= 5/2

                                                         2x - 1= 5/2 =>2x= 5/2 + 1= 7/2

                                                                               x= 7/2 : 2 =7/4

a: =>3x+10-2x=0

hay x=-10

c: \(\Leftrightarrow3x^2-3x^2+6x=36\)

=>6x=36

hay x=6

Bài 1: 

a: \(=6x^3-10x^2+6x\)

b: \(=-2x^3-10x^2-6x\)

Bài 4: 

a: =>3x+10-2x=0

=>x=-10

c: =>3x²-3x²+6x=36

=>6x=36

hay x=6

Bài 1:

\(a,=6x^3-10x^2+6x\\ b,=-2x^3-10x^2-6x\)

Bài 4:

\(a,\Leftrightarrow3x+10-2x=0\Leftrightarrow x=-10\\ b,\Leftrightarrow x\left(2x^2+9x-5\right)-\left(2x^3+9x^2+x+4,5\right)=3,5\\ \Leftrightarrow2x^3+9x^2-5x-2x^3-9x^2-x-4,5=3,5\\ \Leftrightarrow-6x=8\Leftrightarrow x=-\dfrac{4}{3}\\ c,\Leftrightarrow3x^2-3x^2+6x=36\Leftrightarrow x=6\)

Bài 1:

\(a,=7xy\left(2x-3y+4xy\right)\\ b,=x\left(x+y\right)-5\left(x+y\right)=\left(x-5\right)\left(x+y\right)\\ c,=\left(x-y\right)\left(10x+8\right)=2\left(5x+4\right)\left(x-y\right)\\ d,=\left(3x+1-x-1\right)\left(3x+1+x+1\right)\\ =2x\left(4x+2\right)=4x\left(2x+1\right)\\ e,=5\left[\left(x-y\right)^2-4z^2\right]=5\left(x-y-2z\right)\left(x-y+2z\right)\\ f,=x^2+8x-x-8=\left(x+8\right)\left(x-1\right)\\ g,\left(x+y\right)^3-\left(x+y\right)=\left(x+y\right)\left[\left(x+y\right)^2-1\right]\\ =\left(x+y\right)\left(x+y-1\right)\left(x+y+1\right)\\ h,=x^2+3x+x+3=\left(x+3\right)\left(x+1\right)\)

Rảnh rỗi thật sự .-.