## 1.a) x ² -10x =0 b) 8x ²-72x=0 c)x ²+9x =0

Question

1.a) x ² -10x =0
b) 8x ²-72x=0
c)x ²+9x =0

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1 year 2020-10-20T23:28:42+00:00 2 Answers 73 views 0

## Answers ( )

1. a, x^2-10x=0

<=>x.(x-10)=0

<=> $$\left[ \begin{array}{l}x=0\\x-10=0\end{array} \right.$$

<=> $$\left[ \begin{array}{l}x=0\\x=10\end{array} \right.$$

Vậy x ∈ {0;10}

b,8x^2-72x=0

<=> 8x(x-9)=0

<=> $$\left[ \begin{array}{l}8x=0\\x-9=0\end{array} \right.$$

<=> $$\left[ \begin{array}{l}x=0\\x=9\end{array} \right.$$

c,x^2+9x=0

<=>x(x+9)=0

<=> $$\left[ \begin{array}{l}x=0\\x+9=0\end{array} \right.$$

<=> $$\left[ \begin{array}{l}x=0\\x=-9\end{array} \right.$$

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2. Đáp án:

Giải thích các bước giải:

$a)x^2-10x=0$

$⇔x(x-10)=0$

$$\left[ \begin{array}{l}x=0\\x-10=0\end{array} \right.$$

$$\left[ \begin{array}{l}x=0\\x=10\end{array} \right.$$

$b)8x^2-72x=0$

$⇔8x(x-9)=0$

$$\left[ \begin{array}{l}8x=0\\x-9=0\end{array} \right.$$

$$\left[ \begin{array}{l}x=0\\x=9\end{array} \right.$$

$c)x^2+9x =0$

$⇔x(x+9) =0$

$$\left[ \begin{array}{l}x=0\\x+9=0\end{array} \right.$$

$$\left[ \begin{array}{l}x=0\\x=-9\end{array} \right.$$