( 2,8x - 32 ) : 2/3 = -90

( 2,8x - 32 )        = -60

  2,8x                 = -60 +32

  2,8x                 = -28

      x                  = -28 : 2,8

      x                   = -10

(2,8x - 32) : 2\3 = -90

2,8x - 32          = -90 . 2/3

2,8x - 32          = -60

2,8x                = -60 + 32

2,8x                = -28

x                    = -28 : 2,8

x                    = -10

= -90.\(\dfrac{2}{3}\)

2 , 8 x - 32 = -60

2 , 8 x = -60 + 32

2 , 8 x = -28

x = -28 : 2, 8

x = -10

\(\left(2,8x-32\right):\dfrac{2}{3}=-90\\ \left(2,8x-32\right)=-90.\dfrac{2}{3}=-60\\ 2,8x=-60+32=-28\\ x=-28:2,8=-10\)

\(\left(2,8x-32\right):\frac{2}{3}=-90\)

\(\Rightarrow\left(2,8x-32\right)=-90\cdot\frac{2}{3}\)

\(\Rightarrow\left(2,8x-32\right)=-60\)

\(\Rightarrow2,8x=-60+32\)

\(\Rightarrow2,8x=-28\)

\(\Rightarrow x=-10\)

\(\left(2,8x-32\right):\frac{2}{3}=-90\)

\(2,8x-32=-90.\frac{2}{3}=\frac{-90.2}{3}=\frac{-30.2}{1}=-60\)

\(\frac{14}{5}x=-60+32=-28\)

\(x=-28:\frac{14}{5}=-28.\frac{5}{14}=\frac{-28.5}{14}=\frac{-2.5}{1}=-10\)

(2,8X-32):2/3=-90

2,8X -32=-90*2/3

2,8X-32=-60

2,8X=-60+32

2,8X=-28

X=-28/2,8

X=-10

28/10.x-32=-90÷2/3

28/10.x-32=135

28/10.x=135+32

28/10.x=167

x=167÷28/10

x=835/14

Bạn tu rút gọn nha ok 

Học tot

a: \(=\dfrac{7}{5}\cdot\dfrac{15}{49}-\dfrac{12+10}{15}:\dfrac{11}{5}\)

\(=\dfrac{3}{7}-\dfrac{22}{15}\cdot\dfrac{5}{11}=\dfrac{3}{7}-\dfrac{2}{3}=\dfrac{9-14}{21}=\dfrac{-5}{21}\)

b: =>2,8x-32=-60

=>2,8x=-28

hay x=-10

a) x=-10

b)x=2

\(a,\dfrac{7}{12}-\left(x+\dfrac{7}{10}\right):\dfrac{6}{5}=\dfrac{5}{4}\)

\(\Leftrightarrow\dfrac{7}{12}-x-\dfrac{7}{10}:\dfrac{6}{5}=\dfrac{5}{4}\)

\(\Leftrightarrow\dfrac{7}{12}-x-\dfrac{7}{12}=\dfrac{5}{4}\)

\(\Leftrightarrow\dfrac{7}{12}-x=\dfrac{5}{4}+\dfrac{7}{12}\)

\(\Leftrightarrow\dfrac{7}{12}-x=\dfrac{11}{6}\)

\(\Leftrightarrow x=\dfrac{7}{12}-\dfrac{11}{6}\)

\(\Leftrightarrow\dfrac{-5}{4}\)

tham khảo !

a,    x=10

b,   x= 2

A/\(\left(2,8x-32\right):\frac{2}{3}=-90\)

\(\left(\frac{28}{10}x-32\right)=\frac{-90}{1}.\frac{2}{3}\)

\(\left(\frac{14}{5}x-32\right)=\frac{-30}{1}.\frac{2}{1}\)

\(\left(\frac{14}{5}x-32\right)=-60\)

\(\frac{14}{5}x=-60+32\)

\(\frac{14}{5}x=-28\)

\(x=\frac{-28}{1}:\frac{14}{5}\)

\(x=\frac{-28}{1}.\frac{5}{14}\)

\(x=\frac{-2}{1}.\frac{5}{1}=-10\)

B/\(\left(4,5-2x\right).1\frac{4}{7}=\frac{11}{14}\)

\(\left(\frac{45}{10}-2x\right).\frac{11}{7}=\frac{11}{14}\)

\(\left(\frac{9}{2}-2x\right)=\frac{11}{14}:\frac{11}{7}\)

\(\left(\frac{9}{2}-2x\right)=\frac{11}{14}.\frac{7}{11}\)

\(\left(\frac{9}{2}-2x\right)=\frac{1}{2}.\frac{1}{1}=\frac{1}{2}\)

\(2x=\frac{9}{2}-\frac{1}{2}\)

\(2x=\frac{8}{2}\)

\(x=\frac{8}{2}:\frac{2}{1}=\frac{8}{2}.\frac{1}{2}\)

\(x=\frac{4}{2}.\frac{1}{1}=\frac{4}{2}=2\)