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K

kool_boy_98

$a/ x^2 -10x = -25$
$\Longleftrightarrow x^2-10x+25=0$
$\Longleftrightarrow (x-5)^2=0$
$\Longleftrightarrow x-5=0$
$\Longleftrightarrow x=5$

$b/ (x+8)^2 = 121$
$\Longleftrightarrow (x+8)^2-121=0$
$\Longleftrightarrow (x+8-11)(x+8+11)=0$
$\Longleftrightarrow (x-3)(x+19)=0$
$\Longleftrightarrow$ Hoặc $x=3$ hoặc $x=-19$

$c/x^2 + 8x +16 =0$
$\Longleftrightarrow (x+4)^2=0$
$\Longleftrightarrow x+4=0$
$\Longleftrightarrow x=-4$

$d/ 4x^2 -12x =-9$
$\Longleftrightarrow 4x^2-12x+9=0$
$\Longleftrightarrow (2x-3)^2=0$
$\Longleftrightarrow 2x-3=0$
$\Longleftrightarrow x=\frac{3}{2}$
 
H

hiensau99

a/ $x^2 -10x = -25$
$\to x^2 -10x +25= 0 $
$\to (x -5)^2= 0 $
$\to x -5= 0 $
$\to x =5 $

b/ $(x+8)^2 = 121$
$\to (x+8)^2-11^2=0$
$\to (x+8+11)(x+8-11)=0$
$\to (x+19)(x-3)=0$
$\to \left[\begin{matrix} x+19=0\\ x-3=0\end{matrix}\right. \to \left[\begin{matrix} x=-19\\ x=3 \end{matrix}\right. $

c/$x^2 + 8x +16 =0 $
$\to x^2+4.2x+4^2=0$
$\to (x+4)^2=0$
$\to x+4=0 \to x=-4$

d/ $4x^2 -12x =-9$
$\to 4x^2 -12x +9=0$
$\to (2x)^2-2.2x.3+3^2=0$
$\to (2x-3)^2=0$
$\to 2x-3=0$
$\to x=\dfrac{3}{2}$
 
B

braga

[TEX]e, \ pt\Leftrightarrow x(6x^2+x-2)=0 \Leftrightarrow \[x=0 \\ 6x^2+x-2=0[/TEX] [TEX]\Leftrightarrow \[x=0 \\ x=\frac{1}{2} \\ x=-\frac{2}{3}[/TEX]
 
S

subaru_99

a)$$x^2 -10x = -25$$
\Leftrightarrow$$x^2 - 10x + 25 = 0$$
\Leftrightarrow$$(x - 5)^2 = 0$$
\Leftrightarrow$$x - 5 = 0$$
\Rightarrow$$x = 5 $$

b)$$(x + 8)^2 = 121$$
\Leftrightarrow$$(x + 8)^2 - 11^2 = 0$$
\Leftrightarrow$$(x + 8 + 11)(x + 8 - 11) = 0$$
\Leftrightarrow$$(x + 19)(x - 3) = 0$$
[tex]\left\[ \begin{array}{l} x + 19 = 0 \\ x - 3 = 0 \end{array} \right.[\tex] [tex]\left\{ \begin{array}{l} x+\sqrt{y} = 1 \\ x - y^x =3 \end{array} \right.[/tex]


c)$$x^2 + 8x +16 =0$$


d)$$4x^2 -12x =-9$$


e)$$6x^3 +x^2 = 2x$$
 
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