=>1/4:(x-2/3)=2

=>(x-2/3)=1/8

=>x=1/8+2/3=3/24+16/24=19/24

13/4 - 1/4 : ( x - 2/3 )= 5/4

\(\Rightarrow\) 1/4 : ( x- 2/3 ) = 13/4 - 5/4

\(\Rightarrow\) 1/4 : ( x- 2/3)= 2

\(\Rightarrow\) x - 2/3 = 1/4 :2

\(\Rightarrow\) x- 2/3 = 1/8

\(\Rightarrow\) x= 1/8 +2/3 =19/24

Vậy x = 19/24

\(\dfrac{13}{4}-\dfrac{1}{4}\div\left(x-\dfrac{2}{3}\right)=\dfrac{5}{4}\\ \Rightarrow\dfrac{1}{4}\div\left(x-\dfrac{2}{3}\right)=\dfrac{13}{4}-\dfrac{5}{4}\\ \Rightarrow\dfrac{1}{4}\div\left(x-\dfrac{2}{3}\right)=\dfrac{8}{4}=2\\ \Rightarrow x-\dfrac{2}{3}=\dfrac{1}{4}\div2\\ \Rightarrow x-\dfrac{2}{3}=\dfrac{1}{4}\times\dfrac{1}{2}\\ \Rightarrow x-\dfrac{2}{3}=\dfrac{1}{8}\\ \Rightarrow x-\dfrac{16}{24}=\dfrac{3}{24}\\ \Rightarrow x=\dfrac{3}{24}+\dfrac{16}{24}\\ \Rightarrow x=\dfrac{19}{24}\)

Vậy \(x=\dfrac{19}{24}\) 

\(tanx=tan\left(\dfrac{3\pi}{11}\right)\Leftrightarrow x=\dfrac{3\pi}{11}+k\pi\)

\(\dfrac{\pi}{4}< x< 2\pi\Rightarrow\dfrac{\pi}{4}< \dfrac{3\pi}{11}+k\pi< 2\pi\)

\(\Rightarrow-\dfrac{1}{44}< k< \dfrac{19}{11}\Rightarrow k=\left\{0;1\right\}\)

\(\Rightarrow\) Phương trình có 2 nghiệm trên khoảng đã cho (ứng với 2 giá trị của k)

Chọn B

x x2 -x x 3 = 4

                = ( 4 x 3 ) - ( 4 x 2 )

                =   12 - 8

                =     4

  k mình nhé

x .2 -x .3 =4

x.(2-3)=4

x.-1=4

x=4:-1

Vậy -4

k mk nha

X x 2 - X x 3 = 4

X x (3 - 2) = 4

X x     1    = 4

X              = 4 : 1

X              = 4

\(\dfrac{3}{x}=\dfrac{1}{y}=\dfrac{6}{2}\)

\(\Rightarrow\dfrac{3}{x}=\dfrac{1}{y}=3\)

\(\Rightarrow\left\{{}\begin{matrix}x=1\\y=\dfrac{1}{3}\end{matrix}\right.\)

x = 1

y = 1/3

x = 1 

y = 1/3. 

Đường thẳng (d): y = (m + 1)x - 7 đi qua điểm có A(-1; 3). 

\(\Rightarrow\) \(\text{3 = (m + 1).(-1) - 7.}\)

\(\Leftrightarrow\) \(\text{m + 1 = -10.}\)

\(\Rightarrow\) Hệ số góc của đường thẳng (d) là: \(-10.\)

\(\Rightarrow\) Chọn \(B.-10.\)

a) \(x=-\dfrac{3}{5}\times\dfrac{9}{7}=-\dfrac{27}{35}\)

b) \(x\left(0,4-\dfrac{1}{5}\right)=\dfrac{3}{4}\)

\(x=\dfrac{3}{4}:\dfrac{1}{5}=\dfrac{15}{4}\)

a, \(x=-3,5.\dfrac{9}{7}=-\dfrac{9}{2}\)

b, \(\dfrac{2}{5}x-\dfrac{1}{5}x=\dfrac{3}{4}\Leftrightarrow\dfrac{1}{5}x=\dfrac{3}{4}\Leftrightarrow x=\dfrac{3}{4}:\dfrac{1}{5}=\dfrac{15}{4}\)

x=\(\dfrac{9}{7}x-3.5\)

x=\(\dfrac{-9}{5}\)

mình chỉ biết bằng 2/99

1-1/3=2/3; 1-1/4=3/4; 1-1/5=4/5....; 1-1/99=98/99

=> A= (2.3.4.5....98):(3.4.5....99)=2/99

Đs: 2/99

1-1/3=3/3-1/3=2/3

1-1/4=4/4-1/4=3/4

1-1/5=5/5-1/5=4/5

2/3×3/4×4/5×....×98/99

=2/99

\(N=\left|x+3\right|+\left|x+4\right|+\left|x+5\right|\)

\(\left|x+3\right|,\left|x+4\right|,\left|x+5\right|\ge0\)

\(\Rightarrow N\ge0\)

\(N=\left(x+3\right)+\left(x+4\right)+\left(x+5\right)\ge0\)

\(N=\left(x+x+x\right)+\left(3+4+5\right)\)

\(N=3x+12\)

\(\Rightarrow N=3x\ge12\)

\(\Rightarrow N=x\ge4\)

\(\Rightarrow N\ge4\)