Toán 7.(-x)-|x+9| = -9- 57 Giải giúp mik vs ạ, mik đag cần gấp 05/12/2021 By Ariana 7.(-x)-|x+9| = -9- 57 Giải giúp mik vs ạ, mik đag cần gấp
$7.(-x)-|x+9|=-9-57$ $\Leftrightarrow -7x-|x+9|= -66$ $\Leftrightarrow 7x+|x+8|= 66$ (*) – TH1: $x \ge -8$: (*) $\Leftrightarrow 7x+x+8=66$ $\Leftrightarrow 8x=58$ $\Leftrightarrow x= 7,25$ (TM) – TH2: $x < -8$: (*) $\Leftrightarrow 7x-x-8=66$ $\Leftrightarrow 6x= 74$ $\Leftrightarrow x= \frac{37}{3}$ (loại) Vậy $S= \{7,25\}$ Trả lời
7 . (-x) – |x+9| = -9 – 57 ⇒-7x – |x+9| = -66 ⇒\(\left[ \begin{array}{l}-7x-(x+9)=-66\\-7x+(x+9)=-66\end{array} \right.\) ⇒\(\left[ \begin{array}{l}-7x-x-9=-66\\-7x+x+9=-66\end{array} \right.\) ⇒\(\left[ \begin{array}{l}-8x=-57\\-6x=-75\end{array} \right.\) ⇒\(\left[ \begin{array}{l}x=57/8\\x=25/2\end{array} \right.\) Vậy x=$\frac{57}{8}$ hoặc x=$\frac{25}{2}$ Chúc e học tốt! Trả lời
$7.(-x)-|x+9|=-9-57$
$\Leftrightarrow -7x-|x+9|= -66$
$\Leftrightarrow 7x+|x+8|= 66$ (*)
– TH1: $x \ge -8$:
(*) $\Leftrightarrow 7x+x+8=66$
$\Leftrightarrow 8x=58$
$\Leftrightarrow x= 7,25$ (TM)
– TH2: $x < -8$:
(*) $\Leftrightarrow 7x-x-8=66$
$\Leftrightarrow 6x= 74$
$\Leftrightarrow x= \frac{37}{3}$ (loại)
Vậy $S= \{7,25\}$
7 . (-x) – |x+9| = -9 – 57
⇒-7x – |x+9| = -66
⇒\(\left[ \begin{array}{l}-7x-(x+9)=-66\\-7x+(x+9)=-66\end{array} \right.\)
⇒\(\left[ \begin{array}{l}-7x-x-9=-66\\-7x+x+9=-66\end{array} \right.\)
⇒\(\left[ \begin{array}{l}-8x=-57\\-6x=-75\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=57/8\\x=25/2\end{array} \right.\)
Vậy x=$\frac{57}{8}$ hoặc x=$\frac{25}{2}$
Chúc e học tốt!