Tìm x biết: (5-2x).(2x+7)=(2x-5).(2x+5) 12/08/2021 Bởi Abigail Tìm x biết: (5-2x).(2x+7)=(2x-5).(2x+5)
Đáp án: (5-2x).(2x+7)=(2x-5).(2x+5) ⇔(5-2x).(2x+7)-(2x-5).(2x+5)=0 ⇔(5-2x).(2x+7)+(5-2x).(2x+5)=0 ⇔(5-2x)(2x+7+2x+5)=0 ⇔(5-2x)(4x+12)=0 ⇔(5-2x)4(x+3)=0 ⇔(5-2x)(x+3)=0 ⇔\(\left[ \begin{array}{l}5-2x=0\\x+3=0\end{array} \right.\) ⇔\(\left[ \begin{array}{l}-2x=-5\\x=-3\end{array} \right.\) ⇔\(\left[ \begin{array}{l}x=$\frac{5}{2}$ \\x=-3\end{array} \right.\) Giải thích các bước giải: chúc bn hk tốt Bình luận
$(5-2x)(2x+7)=(2x-5)(2x+5)$ $⇔(5-2x)(2x+7)=-(5-2x)(2x+5)$ $⇔(5-2x)(2x+7)+(5-2x)(2x+5)=0$ $⇔(5-2x)(2x+7+2x+5)=0$ $⇔(5-2x)(4x+12)=0$ $⇔4(5-2x)(x+3)=0$ $⇔\left[ \begin{array}{l}5-2x=0\\x+3=0\end{array} \right.⇔\left[ \begin{array}{l}x=\frac{5}{2}\\x=-3\end{array} \right.$ Vậy $x=\frac{5}{2}$ hoặc $x=-3$. Bình luận
Đáp án:
(5-2x).(2x+7)=(2x-5).(2x+5)
⇔(5-2x).(2x+7)-(2x-5).(2x+5)=0
⇔(5-2x).(2x+7)+(5-2x).(2x+5)=0
⇔(5-2x)(2x+7+2x+5)=0
⇔(5-2x)(4x+12)=0
⇔(5-2x)4(x+3)=0
⇔(5-2x)(x+3)=0
⇔\(\left[ \begin{array}{l}5-2x=0\\x+3=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}-2x=-5\\x=-3\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=$\frac{5}{2}$ \\x=-3\end{array} \right.\)
Giải thích các bước giải:
chúc bn hk tốt
$(5-2x)(2x+7)=(2x-5)(2x+5)$
$⇔(5-2x)(2x+7)=-(5-2x)(2x+5)$
$⇔(5-2x)(2x+7)+(5-2x)(2x+5)=0$
$⇔(5-2x)(2x+7+2x+5)=0$
$⇔(5-2x)(4x+12)=0$
$⇔4(5-2x)(x+3)=0$
$⇔\left[ \begin{array}{l}5-2x=0\\x+3=0\end{array} \right.⇔\left[ \begin{array}{l}x=\frac{5}{2}\\x=-3\end{array} \right.$
Vậy $x=\frac{5}{2}$ hoặc $x=-3$.