Tìm X:
XX - 2X x 2 + 68 = 100
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xx - 2x x 2 + 68 = 100
=> x . ( x - 4 ) + 68 = 100
=> x . ( x - 4 ) = 100 - 68
=> x . ( x - 4 ) = 32
Ta có :
32 = 8 . ( 8 - 4 )
=> x . ( x - 4 ) = 8 . ( 8 - 4 )
=> x = 8
Vậy x = 8
Học vui!
xx - 2x x 2 = 68
x(x - 4) + 68 = 100
x(x - 4) = 32
X x(x - 4) = 8 x (8 - 4)
Vậy x = 8
a: x(x+5)^2=x+5
=>(x+5)(x^2+5x-1)=0
=>x+5=0 hoặc x^2+5x-1=0
=>\(x\in\left\{-5;\dfrac{-5+\sqrt{29}}{2};\dfrac{-5-\sqrt{29}}{2}\right\}\)
b: x(x-2)=(x-2)
=>(x-2)(x-1)=0
=>x=2 hoặc x=1
X x 9,01 - X : 100 = 30,6
X x 9,01 - X x 0,01 = 30,6
X x (9,01 - 0,01) = 30,6
X x 9 = 30,6
X = 30,6 : 9
X = 3,4
\(x^3-2x^2+x-2=0\\ \Leftrightarrow x^2\left(x-2\right)+\left(x-2\right)=0\\ \Leftrightarrow\left(x^2+1\right)\left(x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x^2+1=0\\x-2=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x^2=-1\left(vô.lí\right)\\x=2\end{matrix}\right.\\ Vậy:x=2\\ ---\\ 2x\left(3x-5\right)=10-6x\\ \Leftrightarrow6x^2-10x-10+6x=0\\ \Leftrightarrow6x^2-4x-10=0\\ \Leftrightarrow6x^2+6x-10x-10=0\\ \Leftrightarrow6x\left(x+1\right)-10\left(x+1\right)=0\\ \Leftrightarrow\left(6x-10\right)\left(x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}6x-10=0\\x+1=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{3}\\x=-1\end{matrix}\right.\)
\(4-x=2\left(x-4\right)^2\\ \Leftrightarrow4-x=2\left(x^2-8x+16\right)\\ \Leftrightarrow2x^2-16x+32+x-4=0\\ \Leftrightarrow2x^2-15x+28=0\\ \Leftrightarrow2x^2-8x-7x+28=0\\ \Leftrightarrow2x\left(x-4\right)-7\left(x-4\right)=0\\ \Leftrightarrow\left(2x-7\right)\left(x-4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}2x-7=0\\x-4=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=4\end{matrix}\right.\\ ---\\ 4-6x+x\left(3x-2\right)=0\\ \Leftrightarrow4-6x+3x^2-2x=0\\ \Leftrightarrow3x^2-8x+4=0\\ \Leftrightarrow3x^2-6x-2x+4=0\\ \Leftrightarrow3x\left(x-2\right)-2\left(x-2\right)=0\\ \Leftrightarrow\left(3x-2\right)\left(x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}3x-2=0\\x-2=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=2\end{matrix}\right.\)
XX-2X x 2 +68=100
\(x^2-4x+68=100\)
\(X^2-4X-32=0\)
(X-8) x(X+4)=0
X=8 hoặc x=-4