\(x\left(x+5\right)\left(x-5\right)-\left(x+2\right)\left(x^2-2x+4\right)=42\)

\(\Leftrightarrow x\left(x^2-25\right)-\left(x^3+8\right)=42\)

\(\Leftrightarrow x^3-25x-x^3-8=42\)

\(\Leftrightarrow-25x-8=42\)

\(\Leftrightarrow-25x=42+8\)

\(\Leftrightarrow-25x=50\)

\(\Leftrightarrow x=-\dfrac{50}{25}=-2\)

\(x-\frac{3}{4}=\frac{2}{-6}\)

\(x-\frac{3}{4}=\frac{-1}{3}\)

\(x=\frac{-1}{3}+\frac{3}{4}\)

\(x=\frac{5}{12}\)

mk giải lun ak

x=2/-6+3/4

x=5/12

/ là dấu phân số nha bạn

k mk

thanks

nhầm rồi

1cong1=

số số hạng: ( 2500 - 2 ) : 2 +1  = 1250 số

tổng: ( 2500 +2  ) . 1250 : 2 = 1563750

Vì: 1250 . 1251 = 1563750

=> x = 1250 

dat \(\frac{x}{5}=\frac{y}{4}=k\)-> x=5k va y=4.k

thay x=5k va y=4k vao x²-y²=1 ta duoc

(5k)²-(4k)²=1

25k²-16k²=1

9k²=1

k²=\(\frac{1}{9}=\left(\frac{1}{3}\right)^2\)

-> k=1/3 hay k=-1/3

voi K=1/3--> x=5.1/3=5/3 va y=4.1/3=4/3

voi K=-1/3->x=5.-1/3=-5/3 va y=4.-1/3=-4/3

a, Xét \(\dfrac{x}{-5}=2\Rightarrow x=-10\)

\(\dfrac{y}{4}=2\Leftrightarrow y=8\)

b, \(xy=6\Rightarrow x;y\inƯ\left(6\right)=\left\{\pm1;\pm2;\pm3;\pm6\right\}\)

\(\dfrac{x-1}{2011}+\dfrac{x-2}{2010}-\dfrac{x-3}{2009}=\dfrac{x-4}{2008}\)

<=> \(\left(\dfrac{x-1}{2011}-1\right)+\left(\dfrac{x-2}{2010}-1\right)-\left(\dfrac{x-3}{2009}-1\right)=\left(\dfrac{x-4}{2008}-1\right)\)

<=> \(\dfrac{x-2012}{2011}+\dfrac{x-2012}{2010}-\dfrac{x-2012}{2009}-\dfrac{x-2012}{2008}=0\)

<=> \(\left(x-2012\right)\left(\dfrac{1}{2011}+\dfrac{1}{2010}-\dfrac{1}{2009}-\dfrac{1}{2008}\right)=0\)

<=> x - 2012 = 0

<=> x = 2012