a: (x-3)(x-1)-x(x-2)=0

=>\(x^2-4x+3-x^2+2x=0\)

=>\(-2x+3=0\)

=>-2x=-3

=>\(x=\dfrac{3}{2}\)

b: \(\left(x+2y\right)^2-\left(2x-y\right)^2\)

\(=\left(x+2y+2x-y\right)\left(x+2y-2x+y\right)\)

\(=\left(3x+y\right)\left(-x+3y\right)\)

\(\Leftrightarrow x-2015>0\left(-5< 0\right)\\ \Leftrightarrow x>2015\)

\(\left(2x-6\right)\times\left(5-x\right)=0\)

\(2x-6=0;5-x=0\)

\(x=3;x=5\)

Vậy: \(x=3;x=5\)

$\left(2x-6\right)\times \left(5-x\right)=0$

$2x-6=0;5-x=0$

$x\; =3,\; x\; =\; 5$

Vậy x = 3 và 5.

a, x x 5,8=19,72

   x=19,72:5,8

   x=3.4

b,x:5,6=34,5

  x=34,5 x 5,6

   x=193,2

\(\sqrt{x^2-2x+1}=\sqrt{3+2\sqrt{2}}\)

\(\Leftrightarrow\sqrt{\left(x-1\right)^2}=\sqrt{\left(\sqrt{2}+1\right)^2}\)

\(\Leftrightarrow\left|x-1\right|=\sqrt{2}+1\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=\sqrt{2}+1\\x-1=-\sqrt{2}-1\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=2+\sqrt{2}\\x=-\sqrt{2}\end{matrix}\right.\)

Lời giải:

PT $\Leftrightarrow \sqrt{(x-1)^2}=\sqrt{(\sqrt{2}+1)^2}$

$\Leftrightarrow |x-1|=|\sqrt{2}+1|=\sqrt{2}+1$

$\Leftrightarrow x-1=\pm (\sqrt{2}+1)$

$\Leftrightarrow x=2+\sqrt{2}$ hoặc $x=-\sqrt{2}$

x = (-99; -98;-97;-96;...;98;99;100)

Do -100 < x ≤ 100

⇒ x ∈ {-99; -98; -97; ...; 98; 99; 100}

\(a,\Leftrightarrow\left[{}\begin{matrix}x-8=0\\x^3+8=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=8\\x^3=-8\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=8\\x=-2\end{matrix}\right.\\ b,\Leftrightarrow4x-3-x-5=30-3x\\ \Leftrightarrow4x-x+3x=30+5+3\\ \Leftrightarrow6x=38\\ \Leftrightarrow x=\dfrac{19}{3}\)

\(x\times\)2,5 + 2,5 \(\times\) 0,6  = 1,8 : 0,2

\(x\)\(\times\)2,5 + 1,5 = 9

\(x\) \(\times\) 2,5 = 9 - 1,5

\(x\times\)2,5 = 7,5

\(x\)         = 7,5 : 2,5

\(x\)         =  3

\(x\times2,5+2,5\times0,6=1,8:0,2\\ 2,5\times\left(x+0,6\right)=9\\ x+0,6=9:2,5\\ x+0,6=3,6\\ x=3,6-0,6\\ x=3\)

dạ con cảm ơn cô ạ

x³-3x²+x-3=0

=(x³+x)-(3x²+3)
=x(x²+1)-3(x²+1)

=(x²+1)(x-3)
=>x²+1=0 hoặc x-3=0
=>x²=-1(vô nghiệm) hoặc x=3
Vậy x=3

(x³-3x²)+(x-3)

x²(x-3)+(x-3)

(x-3)(x²+1)