= 855x45+ 855x55

= 855x( 45+55)

=855x100

=85500

x+45=45-45+55:55

x+45=0+1

x+45=1

x=1-45

x=-44

k nhé mk vừa k bn rùi

x + 45 = 45 - 45 + 55 : 55

x + 45 = 45 - 45 + 1

x + 45 = 0 + 1 

x + 45 = 1

        x = 1 - 45

        x = -44

bài toán này hình như sai

45 x ( 55 + 117 ) + 55 x ( 117 - 45 )

= (45 x 55 - 45 x 55) + (45 + 55) x 117

= 0  + 100 x 117 = 11700

\(45\times\left(55+117\right)+55\times\left(117-45\right)\)

\(=45\times55+45\times117+55\times117-55\times45\)

\(=\left(45\times55-45\times55\right)+45\times117+55\times117\)

\(=45\times117+55\times117\)

\(=117\times\left(45+55\right)\)

\(=117\times100\)

\(=11700\)

\(\dfrac{x-45}{55}+\dfrac{x-47}{53}=\dfrac{x-55}{45}+\dfrac{x-53}{47}\)

\(\Leftrightarrow\left(\dfrac{x-45}{55}-1\right)+\left(\dfrac{x-47}{53}-1\right)=\left(\dfrac{x-55}{45}-1\right)+\left(\dfrac{x-53}{47}-1\right)\)

\(\Leftrightarrow\dfrac{x-100}{55}+\dfrac{x-100}{53}=\dfrac{x-100}{45}+\dfrac{x-100}{47}\)

\(\Leftrightarrow\dfrac{x-100}{55}+\dfrac{x-100}{53}-\dfrac{x-100}{45}-\dfrac{x-100}{47}=0\)

\(\Leftrightarrow\left(x-100\right)\left(\dfrac{1}{55}+\dfrac{1}{53}-\dfrac{1}{45}-\dfrac{1}{47}\right)=0\)

Do \(\dfrac{1}{55}+\dfrac{1}{53}-\dfrac{1}{45}-\dfrac{1}{47}\ne0\) nên x - 100 = 0 <=> x = 100

= 85500 nhé

tíck mik nha các bạn yêu dấu

(900-45)x45+(800+55)x55

=855x45+855x55

=855x(45+55)

=855x100

=85500

( 900 - 45 ) x 45 + ( 800 + 55 ) x 55

= 855 x 45 + 855 x 55

= 855 x ( 45 + 55 )

= 855 x 100

= 85500

\(x:2+250.4=55.61+69.55-45.37-93.45\)

\(\Leftrightarrow x:2+1000=55\left(61+69\right)-45\left(37+93\right)\)

\(\Leftrightarrow x:2+1000=55.130-45.130\)

\(\Leftrightarrow x:2+1000=130\left(55-45\right)\)

\(\Leftrightarrow x:2+1000=130.10\)

\(\Leftrightarrow x:2+1000=1300\)

\(\Leftrightarrow x:2=1300-1000=300\)

\(\Leftrightarrow x=300.2=600\)

Vậy \(x=600\)

X:2+250*4=55*61+69*55-45*37-93*45

X:2+250*4=(55*61+69*55)-(45*37+93*45)

X:2+1000=55*(61+69)-45*(37+93)

X:2+1000=55*130-45*130

X:2+1000=(55-45)*130

X:2+1000=10*130

X:2+1000=1300

X:2=1300-1000

X:2=300

X=300*2

X=600

Vậy X = 600

<=>x-45/55 -1 + x-47/53  -1=x-55/45 -1 + x-53/47-1

<=>x-100/55 + x-100/53 = x-100/45 + x-100/47

<=>(x-100)(1/55 + 1/53 - 1/45 - 1/47 )=0

vi (1/55 + 1/53 - 1/45 - 1/47 ) luon khac 0 nen x-100=0 <=>x=100

\(\frac{x-45}{55}+\frac{x-47}{53}=\frac{x-55}{45}+\frac{x-53}{47}\)

\(\Rightarrow\frac{x-45}{55}-1+\frac{x-47}{53}-1=\frac{x-55}{45}-1+\frac{x-53}{47}-1\)

\(\Rightarrow\frac{x-100}{55}+\frac{x-100}{53}=\frac{x-100}{45}+\frac{x-100}{47}\)

\(\Rightarrow\frac{x-100}{55}+\frac{x-100}{53}-\frac{x-100}{45}-\frac{x-100}{47}=0\)

\(\Rightarrow\left(x-100\right)\left(\frac{1}{55}+\frac{1}{53}-\frac{1}{45}-\frac{1}{47}\right)=0\)

\(\Rightarrow x-100=0\).Do \(\frac{1}{55}+\frac{1}{53}-\frac{1}{45}-\frac{1}{47}\ne0\)

\(\Rightarrow x=100\)

\(\frac{x-45}{55}+\frac{x-47}{53}=\frac{x-55}{45}+\frac{x-53}{47}\)

\(\frac{x-45}{55}-1-\frac{x-47}{53}-1=\frac{x-55}{45}-1+\frac{x-53}{47}-1\)

\(\frac{x-100}{55}+\frac{x-100}{53}=\frac{x-100}{45}+\frac{x-100}{47}\)

\(\frac{x-100}{55}+\frac{x-100}{53}-\frac{x-100}{45}-\frac{x-100}{47}=0\)

(x-100)(\(\frac{1}{55}+\frac{1}{53}-\frac{1}{45}-\frac{1}{47}=0\)

-> x-100 = 0 -> x = 100

mà \(\frac{1}{55}+\frac{1}{53}-\frac{1}{45}-\frac{1}{47}\) khác 0

Vậy x = 100

 x = 100 nhé

\(\frac{x-45}{55}+\frac{x-47}{53}=\frac{x-55}{45}+\frac{x-53}{47}\)

\(\Leftrightarrow\frac{x-45}{55}-1+\frac{x-47}{53}-1=\frac{x-55}{45}-1+\frac{x-53}{47}-1\)

\(\Leftrightarrow\frac{x-45-55}{55}+\frac{x-47-53}{47}-\frac{x-55-45}{45}-\frac{x-53-47}{47}=0\)

\(\Leftrightarrow\frac{x-100}{55}+\frac{x-100}{47}-\frac{x-100}{45}-\frac{x-100}{47}=0\)

\(\Leftrightarrow\left(x-100\right)\left(\frac{1}{55}+\frac{1}{53}-\frac{1}{45}-\frac{1}{47}\right)=0\)

\(\Leftrightarrow x-100=0\)

\(\Leftrightarrow x=100\)

Vậy pt có tập nghiệm S = { 100 }