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\(\frac{x}{2}=\frac{32}{x}\)

\(2x.\frac{x}{2}=2x.\frac{32}{x}\)

\(xx=2.32\)

\(x^2=2.32\)

\(x^2=64\)

\(x^2-64=0\)

\(x^2-8^2=0^2\)

\(\Rightarrow x=0+8\)

\(\left(x+8\right)\left(x-8\right)=0\)

Trường hợp 1                                                                                                                                                      

\(x+8=0\)

\(x=8\)

Trường hợp 2

\(x-8=0\)

\(x=-8\)

Vậy \(x\in\left\{8;-8\right\}\)

       HT nhớ k

\(A=1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{149}-\frac{1}{150}\)

\(=\left(1-\frac{1}{2}\right)+\left(\frac{1}{3}-\frac{1}{4}\right)+...+\left(\frac{1}{149}-\frac{1}{150}\right)\)

\(>\frac{1}{2}+0+...+0=\frac{1}{2}\)

Suy ra \(A>\frac{1}{2}\).

7)\(x.\dfrac{3}{7}\)=\(\dfrac{21}{5}\)-\(\dfrac{2}{7}\)<=>\(\dfrac{3x+2}{7}\)=\(\dfrac{21}{5}\)<=>5(3x-2)=147<=>15x-10=147<=>15x=157<=>x=157/15

8) \(x.\dfrac{7}{6}\)=\(\dfrac{-49}{30}\).2,5<=>\(\dfrac{7x}{6}\)=\(\dfrac{-49.2,5}{30}\)<=>210x=-735<=>x=-7/2

\(\dfrac{x-1}{-4}\)=\(\dfrac{-4}{x-1}\)<=> (x-1)²=16

TH1: x-1=4<=>x=5

TH2:x-1=-4<=>x=-3

xin T.I.C.H

   2xy-6y+x=9

=>2yx-3.2y+x=9

=>2y.(x-3)+x=9

=>2y.(x-3)+(x-3)=9-3

=>(x-3).(2y+1)=6

=>x-3 ;2y+1 ∈∈Ư(6)

  Ư(6)={1 ;-1 ;2 ;-2 ;3 ;-3 ;6 ;-6}

Ta có bảng giá trị

Thử lại các đáp án đều đúng

Vậy (x,y) ∈∈{(5,1) ;(1,-2) ;(9,0),(-3,-1)}

HT

54/31 : 12/64 - 8 = 40/31

k nhé:))

\(=\frac{40}{31}\)