K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

18 tháng 9 2022

\(\left(x-\dfrac{2}{3}\right)\times3=\dfrac{3}{4}\)

\(x-\dfrac{2}{3}=\dfrac{3}{4}:3=\dfrac{1}{4}\)

\(x=\dfrac{1}{4}+\dfrac{2}{3}=\dfrac{11}{12}\)

30 tháng 9 2021

a)
=(x-2)3
b)\(\left(2-x\right)^3\)
c)\(\left(x+\dfrac{1}{3}\right)^3\)
d)\(\left(\dfrac{x}{2}+y\right)^3\)
e)
\(=\left(x-1\right)^2\left(x-1-15\right)+25\left[3\left(x-1\right)-5\right]\)
\(=\left(x-1\right)^2\left(x-16\right)+25\left(3x-3-5\right)\)
\(=\left(x-1\right)^2\left(x-16\right)+25\left(3x-8\right)\)
 

11 tháng 12 2017

Áp dụng tính chất dãy tỉ số bằng nhau ta có:

\(\dfrac{x_1-1}{5}=\dfrac{x_2-2}{4}=\dfrac{x_3-3}{3}=\dfrac{x_4-4}{2}=\dfrac{x_5-5}{1}\)

\(=\dfrac{\left(x_1-1\right)+\left(x_2-2\right)+\left(x_3-3\right)+\left(x_4-4\right)+\left(x_5-5\right)}{5+4+3+2+1}\)

\(=\dfrac{\left(x_1+x_2+x_3+x_4+x_5\right)-\left(1+2+3+4+5\right)}{15}\)

\(=\dfrac{30-15}{15}=1\)

\(\Rightarrow x_1=x_2=x_3=x_4=x_5=6\)

Vậy...

11 tháng 12 2017

Áp dụng tính chất dãy tỉ số bằng nhau ta có:

\(\dfrac{x1-1}{5}\)=\(\dfrac{x2-2}{4}\)\(\dfrac{x3-3}{3}\)=\(\dfrac{x4-4}{2}\)=\(\dfrac{x5-5}{1}\)=\(\dfrac{x1-1+x2-2+x3-3+x4-4+x5-5}{5+4+3+2+1}\)=\(\dfrac{x1+x2+x3+x4+x5-\left(1+2+3+4+5\right)}{15}\)=\(\dfrac{30-15}{15}\)=\(\dfrac{15}{15}\)=1

\(\dfrac{x1-1}{5}\)=1 => x1-1=5 => x1 =6

\(\dfrac{x2-2}{4}\)=1 => x2-2=4 => x2 =6

\(\dfrac{x3-3}{3}\)=1 => x3-3=3 => x3 =6

\(\dfrac{x4-4}{2}\)=1 => x4-4=2 => x4 =6

\(\dfrac{x5-5}{1}\)=1 => x5-5=1 => x5 = 6

Vậy x1=x2=x3=x4=x5 =6

AH
Akai Haruma
Giáo viên
11 tháng 6 2021

\(\frac{3}{4}+\frac{1}{2}+\frac{3}{2}=\frac{3}{4}+\frac{2}{4}+\frac{6}{4}=\frac{3+2+6}{4}=\frac{11}{4}\) em nhé.

\(\dfrac{3}{4}+\dfrac{1}{6}\times3+\dfrac{2}{5}:\dfrac{4}{15}\)

\(=\dfrac{3}{4}+\dfrac{1}{2}+\dfrac{2}{5}\times\dfrac{15}{4}\)

\(=\dfrac{3}{4}+\dfrac{1}{2}+\dfrac{3}{2}\) \(=\dfrac{3+2+3}{4}=\dfrac{8}{4}=2\)

25 tháng 12 2021

Câu 4: 

\(=\dfrac{a\left(a-b\right)-c\left(a-b\right)}{a\left(a+b\right)-c\left(a+b\right)}=\dfrac{a-b}{a+b}\)

29 tháng 5 2021

\(P=\left[\left(\dfrac{-1}{3}\right)^2x^3+\left(2x^2\right)^2+\dfrac{1}{2}\right]-\left[x\left(\dfrac{1}{3}x\right)^2+\dfrac{3}{2^3}+x^4\right]+\left(y-2013\right)^2=\left(\dfrac{1}{9}x^3+4x^4+\dfrac{1}{2}\right)-\left(\dfrac{1}{9}x^3+x^4+\dfrac{3}{8}\right)+\left(y-2013\right)^2=3x^4+\dfrac{1}{8}+\left(y-2013\right)^2\ge\dfrac{1}{8}\).

Dấu "=" xảy ra khi x = 0; y = 2013.

31 tháng 10 2023

a: \(\dfrac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\)

\(=\dfrac{2^{10}\cdot3^8-2\cdot2^9\cdot3^9}{2^{10}\cdot3^8+2^8\cdot3^8\cdot2^2\cdot5}\)

\(=\dfrac{2^{10}\cdot3^8-2^{10}\cdot3^9}{2^{10}\cdot3^8+2^{10}\cdot3^8\cdot5}\)

\(=\dfrac{2^{10}\cdot3^8\left(1-3\right)}{2^{10}\cdot3^8\left(1+5\right)}=\dfrac{-2}{6}=-\dfrac{1}{3}\)

14 tháng 10 2021

a: \(\dfrac{4x^4y-7x^2y+3y}{-3x^2+2y}\)

\(=\dfrac{4x^4y-4x^2y-3x^2y+3y}{-\left(3x^2-2y\right)}\)

\(=\dfrac{4x^2y\left(x^2-1\right)-3y\left(x^2-1\right)}{-\left(3x^2-2y\right)}\)

\(=\dfrac{y\left(x^2-1\right)\left(4x^2-3\right)}{-\left(3x^2-2y\right)}\)

14 tháng 10 2021

a) `(4x^4y-7x^2y+3y).(2y-3x^2y)`

`=8x^4y^2-14x^2y^2+6y^2-12x^6y^2+21x^4y^2-9x^2y^2`

`=29x^4y^2-12x^6y^2-23x^2y^2+6y^2`

b) `(x^2+3x-3/2 x^3):2x - x/2 . (1-3/2 x)`

`=(x+3-3/2 x^2):2 - (x/2 - 3/4 x^2)`

`=x/2 + 3/2 - 3/4 x^2 -x/2 +3/4 x^2`

`=3/2`

c) `(-2x^3-x-3+5x^2):(3-2x)`

`=(3-2x)(x^2-x-1) : (3-2x)`

`=x^2-x-1`

Bài 2:

\(A=\dfrac{2}{-x^2-2x-2}=\dfrac{-2\left(-x^2-2x-2\right)-2x^2-4x-2}{-x^2-2x-2}\) \(=-2+\dfrac{2\left(x+1\right)^2}{-x^2-2x-2}\ge-2\)

  Dấu bằng xảy ra \(\Leftrightarrow x+1=0\Leftrightarrow x=-1\)

  Vậy \(A_{Min}=-2\) khi \(x=-1\)

Bài 1:

a) Ta có: \(2x^2-6=0\)

\(\Leftrightarrow2x^2=6\)

\(\Leftrightarrow x^2=3\)

hay \(x\in\left\{\sqrt{3};-\sqrt{3}\right\}\)

Vậy: \(S=\left\{\sqrt{3};-\sqrt{3}\right\}\)