a) 4x + 3x = 217

  x( 4 + 3 ) = 217

  7x = 217

   x = 217 : 7 = 31

Vậy x = 31
b) 9x - 3x = 216

    ( 9 -3)x = 216

     6x = 216

   x = 216:6 = 36

Vậy x = 36

c) 6x - 3x + 23 = 230

( 6 - 3 )x = 230 - 23

    3x = 207

     x = 207 : 3 = 69

Vậy x = 69

d) 5x + 3x + x = 72

     5x + 3x + 1x = 72

    ( 5 + 3 + 1 )x = 72

                9x = 72

               x = 72 : 9 = 8

Vậy x = 8

Chúc bạn học tốt nhé

a) \(4x+3x=217\)

\(\Rightarrow x\cdot\left(3+4\right)=217\)

\(\Rightarrow7x=217\)

\(\Rightarrow x=\dfrac{217}{7}\)

\(\Rightarrow x=31\)

b) \(9x-3x=216\)

\(\Rightarrow x\cdot\left(9-3\right)=216\)

\(\Rightarrow6x=216\)

\(\Rightarrow x=\dfrac{216}{6}\)

\(\Rightarrow x=36\)

c) \(6x-3x+23=230\)

\(\Rightarrow x\cdot\left(6-3\right)=230-23\)

\(\Rightarrow3x=207\)

\(\Rightarrow x=\dfrac{207}{3}\)

\(\Rightarrow x=69\)

d) \(5x+3x+x=72\)

\(\Rightarrow x\cdot\left(5+3+1\right)=72\)

\(\Rightarrow9x=72\)

\(\Rightarrow x=\dfrac{72}{9}\)

\(\Rightarrow x=8\)

c.on nhìu a

\(216,62+46,216-8,216-4,150\)

\(=216,62+\left(46,216-8,216\right)-4,150\)

\(=216,62+38-4,150\)

\(=254,62-4,150\)

\(=250,47\)

2 phẩy 3 mủ 5 cộng 5 mủ 7 chia 5 mủ 5 trừ 2 mủ 3 cộng phẩy 12 trừ 2016 mủ 0

\(216,62+46,216-8,216-4,150\)

\(=262,836-4,066\)

\(=258,77\)

a: 3x-2=2x-3

=>x=-1

b: 2x+3=5x+9

=>-3x=6

=>x=-2

c: 5-2x=7

=>2x=-2

=>x=-2

d: 10x+3-5x=4x+12

=>5x+3=4x+12

=>x=9

e: 11x+42-2x=100-9x-22

=>9x+42=78-9x

=>18x=36

=>x=2

f: 2x-(3-5x)=4(x+3)

=>2x-3+5x=4x+12

=>7x-3=4x+12

=>3x=15

=>x=5

C 9x^2-4y^2

C

C

\(\frac{1}{3x-2}-\frac{1}{3x+2}-\frac{-3+6}{9x^2-4}=\frac{1}{3x-2}-\frac{1}{3x+2}-\frac{3}{\left(3x-2\right)\left(3x+2\right)}=\frac{3x+2_{ }-3x+2-3}{\left(3x-2\right)\left(3x+2\right)}=\frac{1}{\left(3x-2\right)\left(3x+2\right)}\)

ý b bạn chỉ cần phân tích mẩu ra nó là 1 hằng đẳng thức rồi lấy mẫu chung là hằng đẩng thưcs đó rồi làm như thường

    (−16):(−216)=10:(9x)

=\(\dfrac{-16}{-216}\)=\(\dfrac{10}{9x}\)

=>(-16).9x=10.(-216)

=>9x= \(\dfrac{-2160}{-16}\)

=>9x=135

-> x=135/9=15

Vậy x=15

Ta có: \(\dfrac{-16}{-216}=\dfrac{10}{9x}\)

\(\Leftrightarrow\dfrac{10}{9x}=\dfrac{2}{27}\)

\(\Leftrightarrow9x=135\)

hay x=15

Vậy: x=15

x = 15

\(\frac{1}{3x-2}-\frac{1}{3x+2}-\frac{3x-6}{4-9x^2}\)

\(=\frac{3x+2}{9x^2-4}-\frac{3x-2}{9x^2-4}+\frac{3x-6}{9x^2-4}\)

\(=\frac{3x+2-3x+2+3x-6}{9x^2-4}\)

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

\(=\frac{1}{3x+2}\)

\(\frac{18}{\left(x-3\right)\left(x^2-9\right)}-\frac{3}{x^2-6x+9}-\frac{x^2}{x^2-9}\)

\(=\frac{18}{\left(x-3\right)\left(x-3\right)\left(x+3\right)}\) \(-\frac{3\left(x+3\right)}{\left(x-3\right)\left(x-3\right)\left(x+3\right)}\)\(-\frac{x^2\left(x-3\right)}{\left(x-3\right)\left(x+3\right)\left(x-3\right)}\)

\(=\frac{18-3x-9-x^3+3x^2}{\left(x-3\right)^2\left(x+3\right)}\)

\(=\frac{-x^3+3x^2-3x+9}{\left(x-3^2\right)\left(x+3\right)}\)

\(=\frac{\left(-x^2-3\right)\left(x-3\right)}{\left(x-3^2\right)\left(x+3\right)}\)

\(=\frac{-x^2-3}{\left(x-3\right)\left(x+3\right)}\)

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