Noob ơi, bạn phải đưa vào máy tính ý solve cái là ra x luôn, chỉ tội là đợi hơi lâu

a, 4.(18 - 5x) - 12(3x - 7) = 15(2x - 16) - 6(x + 14) 

=> 72 - 20x - 36x + 84 = 30x - 240 - 6x - 84

=> (72 + 84) + (-20x - 36x) = (30x - 6x) + (-240 - 84) 

=> 156 -  56x = 24x - 324 

=>  24x + 56x = 324 + 156 

=> 80x = 480 

=> x = 480 : 80 =  6 

Vậy x = 6 

b, 5(3x + 5) - 4(2x - 3) = 5x + 3(2x + 12) + 1 

=> 15x + 25 - 8x + 12 = 5x + 6x + 36 + 1 

=> (15x - 8x) + (25 + 12) = 11x + 37 

=> 7x + 37 = 11x + 37 

=> 11x - 7x = 0 

=>  x = 0 

\(1,A=\left(3x+7\right)\left(2x+3\right)-\left(2x+3\right)-\left(3x-5\right)\left(2x+11\right)\\ =6x^2+23x+21-2x-3-6x^2-23x+55\\ =73-2x\left(đề.sai\right)\\ B=x^4+x^3-x^2-2x^2-2x+2-x^4-x^3+3x^2+2x\\ =2\\ 2,\\ a,\Leftrightarrow30x^2+18x+3x-30x^2=7\\ \Leftrightarrow21x=7\Leftrightarrow x=\dfrac{1}{3}\\ b,\Leftrightarrow-63x^2+78x-15+63x^2+x-20=44\\ \Leftrightarrow79x=79\Leftrightarrow x=1\\ c,\Leftrightarrow\left(x+5\right)\left(x^2+3x+2\right)-x^3-8x^2=27\\ \Leftrightarrow x^3+3x^2+2x+5x^2+15x+10-x^3-8x^2=27\\ \Leftrightarrow17x=17\Leftrightarrow x=1\)

\(d,\Leftrightarrow7x-2x^2-3+x^2+x-6=-x^2-x+2\\ \Leftrightarrow9x=11\Leftrightarrow x=\dfrac{11}{9}\)

bài 1:

a) 1/3x=-5/3

x=-5

b) x+12/5=37/15

x=1/15

c) x-1/7=-36/7

x=-5

d) 3x-1/2=0

3x=1/2

x=1/6

e) 2/5+x=1/4

x=-3/20

Viết rõ ra hộ mình với

1/3x=4/3-3=-5/3

x=-5/3:1/3=-5

3,26 + 4/5 =?

làm nhanh lên giúp mình nhé

3,26+4/5=3,26+0,8=3,34

K cho mình cái

\(2\left(5x-8\right)-3\left(4x-5\right)=4\left(3x-4\right)+11\)

\(\Leftrightarrow10x-16-12x+15=12x+16+11\)

\(\Leftrightarrow-2x-1=12x+27\Leftrightarrow-14x-28=0\Leftrightarrow x=-2\)

`x . 3/7 = 2/3`

`=>x= 2/3 : 3/7`

`=>x= 2/3 . 7/3`

`=>x=14/9`

`-----------`

`x : 8/11 = 11/3`

`=>x= 11/3 . 8/11`

`=>x= 88/33`

`=>x=8/3`

`-----------`

`4/7 . x - 2/3 = 1/5`

`=> 4/7 . x = 1/5 +2/3`

`=>4/7 . x =3/15 + 10/15`

`=>4/7 . x =13/15`

`=>x= 13/15 : 4/7`

`=>x= 13/15 xx 7/4`

`=>x= 91/60`

Lời giải:

$x.\frac{3}{7}=\frac{2}{3}$

$x=\frac{2}{3}: \frac{3}{7}=\frac{14}{9}$

-----------

$x: \frac{8}{11}=\frac{11}{3}$

$x=\frac{11}{3}.\frac{8}{11}=\frac{8}{3}$

-----------

$\frac{4}{7}x-\frac{2}{3}=\frac{1}{5}$

$\frac{4}{7}x=\frac{2}{3}+\frac{1}{5}=\frac{13}{15}$

$x=\frac{13}{15}: \frac{4}{7}=\frac{91}{60}$

x × 3/7 = 2/3 

          x = 2/3 ÷ 3/7 

          x = 14/9 

x ÷ 8/11 = 11/3 

             x = 11/3 × 8/11 

             x = 8/3 

4/7 × x - 2/3 = 1/5 

4/7 × x.         = 1/5 + 2/3 

4/7 × x.         = 13/15 

           x.        = 13/15 ÷ 4/7 

           x.        = 91/60

\(a,\frac{1}{2}x+\frac{5}{2}=\frac{7}{2}x-\frac{3}{4}\)

\(\Leftrightarrow\frac{1}{2}x+\frac{5}{2}-\frac{7}{2}x=-\frac{3}{4}\)

\(\Leftrightarrow\frac{1}{2}x-\frac{7}{2}x+\frac{5}{2}=-\frac{3}{4}\)

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

\(\Leftrightarrow-3x=-\frac{13}{4}\)

\(\Leftrightarrow x=-\frac{13}{4}:(-3)=-\frac{13}{4}:\frac{-3}{1}=-\frac{13}{4}\cdot\frac{-1}{3}=\frac{13}{12}\)

\(b,\frac{2}{3}x-\frac{2}{5}=\frac{1}{2}x-\frac{1}{3}\)

\(\Leftrightarrow\frac{2}{3}x-\frac{2}{5}-\frac{1}{2}x=-\frac{1}{3}\)

\(\Leftrightarrow\frac{2}{3}x-\frac{1}{2}x-\frac{2}{5}=-\frac{1}{3}\)

\(\Leftrightarrow\frac{1}{6}x-\frac{2}{5}=-\frac{1}{3}\)

\(\Leftrightarrow\frac{1}{6}x=\frac{1}{15}\)

\(\Leftrightarrow x=\frac{1}{15}:\frac{1}{6}=\frac{1}{15}\cdot6=\frac{6}{15}=\frac{2}{5}\)

\(c,\frac{1}{3}x+\frac{2}{5}(x+1)=0\)

\(\Leftrightarrow\frac{1}{3}x+\frac{2}{5}x+\frac{2}{5}=0\)

\(\Leftrightarrow\frac{11}{15}x=-\frac{2}{5}\)

\(\Leftrightarrow x=-\frac{6}{11}\)

d,e,f Tương tự

\(2\left(x-5\right)+3\left(2-3x\right)=5x+7\)

\(\Leftrightarrow2x-10+6-9x=5x+7\)

\(\Leftrightarrow\left(2x-9x\right)+\left(6-10\right)=5x+7\)

\(\Leftrightarrow-7x-4=5x+7\)

\(\Leftrightarrow-7x-5x=4+7\)

\(\Leftrightarrow-12x=11\)

\(\Leftrightarrow x=\frac{-11}{12}\)

\(3x-5\left(x-2\right)+7=4x-12\)

\(\Leftrightarrow3x-5x-10+7=4x-12\)

\(\Leftrightarrow\left(3x-5x\right)-\left(10-7\right)=4x-12\)

\(\Leftrightarrow-2x-3=4x-12\)

\(\Leftrightarrow-2x-4x=3-12\)

\(\Leftrightarrow-6x=-15\)

\(\Leftrightarrow x=\frac{-15}{-6}=\frac{5}{2}\)

\(\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{x\left(x+3\right)}=\frac{101}{1540}\)

\(\Leftrightarrow\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{x\left(x+3\right)}=\frac{101}{1540}.3\)

\(\Leftrightarrow\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{303}{1540}\)

\(\Leftrightarrow\frac{1}{5}-\frac{1}{x+3}=\frac{303}{1540}\)

\(\Leftrightarrow\frac{5}{5\left(x+3\right)}=\frac{1}{5}-\frac{303}{1540}\)

\(\Leftrightarrow\frac{5}{5x+15}=\frac{308}{1540}-\frac{303}{1540}\)

\(\Leftrightarrow\frac{5}{5x+15}=\frac{5}{1540}\)

\(\Leftrightarrow5x+15=1540\)

\(\Leftrightarrow5x=1540-15\)

\(\Leftrightarrow5x=1525\)

\(\Leftrightarrow x=1525\div5\)

\(\Leftrightarrow x=305\)