\(PT\Leftrightarrow\left(\dfrac{x-70}{130}-1\right)+\left(\dfrac{x-25}{175}-1\right)+\left(\dfrac{x-50}{150}-1\right)+\left(\dfrac{x-275}{25}+3\right)=0\)

\(\Leftrightarrow\left(x-200\right)\left(\dfrac{1}{130}+\dfrac{1}{175}+\dfrac{1}{150}+\dfrac{1}{25}\right)=0\Leftrightarrow x=200\).

Vậy...

a) x- 25%x= 1/2<=>x-1/4x=1/2<=>3/4x=1/2<=>x=1/2:3/4=2/3

b)\(\left(50\%x+2\frac{1}{4}\right).\frac{-2}{3}=\frac{17}{6}\Leftrightarrow-\frac{1}{3}x-\frac{3}{2}=\frac{17}{6}\Leftrightarrow x=-13\)

c)\(\left(3\frac{x}{7}+1\right):\left(-4\right)=\frac{-1}{28}\Leftrightarrow\frac{28+x}{7}:\left(-4\right)=\frac{-1}{28}\Leftrightarrow\frac{28+x}{-28}=\frac{1}{-28}\Leftrightarrow28+x=1\Leftrightarrow x=-27\)

d)\(\left(1\frac{1}{3}-25\%-\frac{5}{12}\right)-2x=1,6:\frac{3}{5}\Leftrightarrow\frac{2}{3}-2x=\frac{8}{3}\Leftrightarrow x=-1\)

a)x-25%x=1/2

x-1/4x=1/2

x.(1-1/4)=1/2

x.3/4=1/2

x=1/2:3/4

x=2/3

Ta có : \(\frac{x}{50}+\frac{x-1}{49}+\frac{x-2}{48}+\frac{x-3}{47}+\frac{x-150}{25}=0\)

=> \(\frac{x}{50}-1+\frac{x-1}{49}-1+\frac{x-2}{48}-1+\frac{x-3}{47}-1+\frac{x-150}{25}+4=0\)

=> \(\frac{x-50}{50}+\frac{x-50}{49}+\frac{x-50}{48}+\frac{x-50}{47}+\frac{x-50}{25}=0\)

=> \(\left(x-50\right)\left(\frac{1}{50}+\frac{1}{49}+\frac{1}{48}+\frac{1}{47}+\frac{1}{25}\right)=0\)

=> \(x-50=0\)

=> \(x=50\)

Vậy phương trình trên có tập nghiệm là \(S=\left\{50\right\}\)

a)50 + x = 180 - 120

 50 + x = 60

 x = 60-50 

 x = 10

b)20-x = 150-140

 20-x = 10

x = 20-10

x = 10

c) 25+x = 100-40

25+x=60

x= 60-25

x=35

d) 100+x =130-25

100+x = 105

x = 105-100

x = 5

e) 143+x = 174-22

143+x = 152

x = 152-143

x = 9 

ỦNG HỘ MK NHÁ

120 + ( 50 + x ) = 180

50 + x = 180 - 120

50 + x = 60

x = 60 - 50

x = 10

140 + ( 20 - x ) = 150

20 - x = 150 - 140

20 - x = 10

x = 20 - 10

x = 10

100 - ( 25 + x ) = 40

25 + x = 100 - 40

25 + x = 60

x = 60 - 25

x = 35

130 - ( 100 + x ) = 25

100 + x = 130 - 25

100 + x = 105

x = 105 - 100

x = 5

174 - ( 143 + x ) = 22

143 + x = 174 - 22

143 + x = 152

x = 152 - 143

x = 9

k mk nha 

Thanks nhìu

\(120+\left(50+x\right)=180\)

\(\Rightarrow50+x=180-120\)

\(\Rightarrow50+x=60\)

\(\Rightarrow x=60-50=10\)

Vậy x = 10

\(140+\left(20-x\right)=150\)

\(\Rightarrow20-x=150-140\)

\(\Rightarrow20-x=10\)

\(\Rightarrow x=20-10=10\)

Vậy x =x10

\(100-\left(25+x\right)=40\)

\(\Rightarrow25+x=100-40\)

\(\Rightarrow25+x=60\)

\(\Rightarrow x=60-25=35\)

Vậy x = 35

\(130-\left(100+x\right)=25\)

\(\Rightarrow100+x=130-25\)

\(\Rightarrow100+x=105\)

\(\Rightarrow x=105-100=5\)

Vậy x = 5

\(174-\left(143+x\right)=22\)

\(\Rightarrow143+x=174-22\)

\(\Rightarrow143+x=152\)

\(\Rightarrow x=152-143=9\)

Vậy x = 9

a. 8,5 x 202,1 + 1,5 x 202,1 + 202,1 x 0,75 + 0,25 x 202,1 - 202,1 

= 202,1 x ( 8,5 + 1,5 + 0,75 + 0,25 - 1) 

= 202,1 x 10 

= 2021 

b. ( 0,8 + 0,5 + 0,75 + 0,5 + 0,2 + 0,25) : 0,5 

= 3 : 0,5 

= 6 

c. 0,4 x 0,75 + 0,4 + 0,4 x 0,5 x 0,4 x 0,25 + 0,5 x 0,4 - 0,4 

= 0,4 x ( 0,75 + 1 + 0,05 + 0,5 - 1) 

= 0,4 x 1,3 

= 0,52

= 

nhầm 

\(\frac{\frac{\frac{2}{5}}{4}}{\frac{\frac{5}{25}}{50}}=\frac{\frac{\frac{2}{5}}{4}}{10}=\frac{\frac{2}{25}}{2}=\frac{4}{25}\)

\(\frac{\frac{\frac{2}{5}}{4}}{\frac{\frac{5}{25}}{50}}=\frac{\frac{2}{5}:4}{\frac{5}{25}:50}=\frac{\frac{2}{5}.\frac{1}{4}}{\frac{5}{25}.\frac{1}{50}}=\frac{\left(\frac{1}{10}\right)}{\left(\frac{1}{250}\right)}=\frac{1}{10}:\frac{1}{250}=\frac{250}{10}=25\)

\(\frac{\frac{\frac{2}{5}}{4}}{\frac{5}{\frac{25}{50}}}=\frac{\frac{2}{5}:4}{5:\frac{25}{50}}=\frac{\frac{2}{5}.\frac{1}{4}}{5.\frac{50}{25}}=\frac{\left(\frac{1}{10}\right)}{10}=\frac{1}{10}:10=\frac{1}{10}.\frac{1}{10}=\frac{1}{100}\)

Chú ý: dấu gạch ngang viết dài hơn để phân biệt tử số và mẫu số của phân số