Đáp án:

 

Giải thích các bước giải:

 

Đáp án:

 

Giải thích các bước giải:

a)3x+1=7x-11

3x+1-7x+11=0

12-4x=0

-4x=-12

x=3

b)2x+x+12=0

3x+12=0

3x=-12

x=-4

c)5-3x=6x+7

5-3x-6x-7=0

-9x-2=0

-9x=2

x=-2/9

d)11-2x=x-1

 11-2x-x+1=0

12-3x=0

-3x=12

x=-4

e)15-8x=9-5x

15-8x-9+5x=0

6-3x=0

-3x=-6

x=2

f)5-(x-6)=4(3-2x)

5-x+6=12-8x

-x+11-12+8x=0

7x-1=0

7x=1

x=1/7

g)2x(x+2)^2-8x^2=2(x-2)(x^2+2x+4)

2x(x^2+4x+4)-8x^2-2(x^3-8)=0

2x^3+8x^2+8x-8x^2-2x^3+16=0

8x+16=0

8(x+2)=0

x+2=0

x=-2

h)(5x-2)/3=(5-3x)/2

[2(5x-2)]/(3*2)=[3(5-3x)]/(2*3)

(10x-4)/6=(15-9x)/6

10x-4=15-9x

10x-4-15+9x=0

19x-19=0

19x=19

x=1

k)(10x+3)/12=1+(6+8x)/9

[3(10x+3)]/(12*3)=36/36+[4(6+8x)/(9*4)

(30x+9)/36=36/36+(24+32x)/36

30x+9=36+24+32x

30x+9-36-24-32x=0

-2x-51=0

-2x=51

x=-51/2

l)(7/8)*x-5(x-9)=(20x+1,5)/6

(3*7x)/(3*8)-[24*5(x-9)]/24=[4(20x+1,5)]/(6*4)

21x/24-[120(x-9)]/24=(80x+6)/24

21x-120x+1080=80x+6

-99x+1080-80x-6=0

-179x+1074=0

-179x=-1074

x=6

m)[(7x-1)/6]+2x=(16-x)/5

[5*(7x-1)/6*5]+(30*2x)/30=[6(16-x)]/(5*6)

(35x-5)/30+60x/30=(96-6x)/30

35x-5+60x=96-6x

95x-5-96+6x=0

101x-101=0

101x=101

x=1

n)(3x+2)/2-(3x+1)/6=(5/3)+2x

[3(3x+2)]/(2*3)-(3x-1)/6=(5*2)/(3*2)+(6*2x)/6

(9x+2)/6-(3x+1)/6=10/6+12x/6

9x+2-3x-1=10+12x

6x+1-10-12x=0

-9-6x=0

-3(3-2x)=0

3-2x=0

-2x=-3

x=3/2

p)(2x+1)^2/5-(x-1)^2/3=(7x^2-14x-5)/15

[3*(4x^2+4x+1)]/3*5-[5(x^2-2x+1)]/3*5=(7x^2-14x-5)/15

(12x^2+12x+3)/15-(5x^2-10x+5)/15=(7x^2-14x-5)/15

12x^2+12x+3-5x^2+10x-5=7x^2-14x-5

7x^2+22x-2-7x^2+14x+5=0

36x+3=0

36x=-3

x=-1/12

q)(10x+3)/12=1+(6+8x)/9

[3(10x+3)]/(12*3)=36/36+[4(6+8x)/(9*4)

(30x+9)/36=36/36+(24+32x)/36

30x+9=36+24+32x

30x+9-36-24-32x=0

-2x-51=0

-2x=51

x=-51/2

r)(x+1)/9+(x+2)/8=(x+3)/7+(x+4)/6

ta thấy -10+1=-9;-10+2=-8;-10+3=-7;-10+4=-6

thay vào đc-9/9+(-8/8)=-7/7+(-6/6)

-1+(-1)=-1+(-1)

-2=-2

vậy x=-10

s)(10x+3)/12=1+(6+8x)/9

[3(10x+3)]/(12*3)=36/36+[4(6+8x)/(9*4)

(30x+9)/36=36/36+(24+32x)/36

30x+9=36+24+32x

30x+9-36-24-32x=0

-2x-51=0

-2x=51

x=-51/2

t)[2(3x+5)]/3-x/2=5-(3x+1)/4

[2*4(3x+5)]/3*4-(6x)/(2*6)=(12*5)/12-[3(3x+1)]/(3*4)

[8(3x+5)]/12-(6x)/12=60/12-(9x+3)/12

24x+40-6x=60-9x-3

18x+40-57+9x=0

27x-17=0

27x=17

x=17/27

v)x/2012+(x+1)/2013+(x+2)/2014+(x+3)/2015+(x+4)/2016=5

ta thấy 2012+0=2012 2012+1=2013;2012+2=2014;2012+3=2015;2012+4=2016

thay vào đc 2012/2012+2013/2013+2014/2014+2015/2015+2016/2016=5

1+1+1+1+1=5

5=5

vậy x=2012

z)(x-15)/17=15

x-15=15*17

x-15=255

x=255+15

x=270

y)(x-3)/2011+(x-2)/2012=(x-2012)/2+(x-2011)/3

ta thấy 2014-3=2011;2014-2=2012;2014-2=2012;2014-3=2011

thay vào đc2011/2011+2012/2012=2/2+3/3

1+1=1+1

2=2

vậy x=2014

w)4(3x-2)-3(x-4)=7x+10

12x-8-3x+12-7x-10=0

2x-6=0

2x=6

x=3