Toán giải phương trình tích a) 9x ²-1=(3x-1)(5x+8) 10/10/2021 By Kaylee giải phương trình tích a) 9x ²-1=(3x-1)(5x+8)
Đáp án: \(\left[ \begin{array}{l}x=\frac{1}{3}\\x=\frac{7}{2}\end{array} \right.\) Giải thích các bước giải: Ta có: a) 9x ²-1=(3x-1)(5x+8) <=> (3x)²-1² = (3x-1)(5x+8) ⇔ (3x-1) (3x+1) = (3x-1)(5x+8) ⇔ (3x-1) (3x+1) – (3x-1)(5x+8) = 0 ⇔ (3x-1) [(3x+1) – (5x+8)] = 0 ⇔ (3x-1) (3x+1 – 5x -8) = 0 ⇔ (3x-1) ( -2x -7) =0 ⇔ \(\left[ \begin{array}{l}3x-1=0\\-2x-7=0\end{array} \right.\) ⇔ \(\left[ \begin{array}{l}3x=1\\2x=-7\end{array} \right.\) ⇔ \(\left[ \begin{array}{l}x=\frac{1}{3}\\x=\frac{7}{2}\end{array} \right.\) Vậy ……….. CHÚC BẠN HỌC TỐT! @sakura #gentleteam Trả lời
Đáp án + Giải thích các bước giải: `a//9x^{2}-1=(3x-1)(5x+8)` `⇔(3x+1)(3x-1)=(3x-1)(5x+8)` `⇔(3x+1)(3x-1)-(3x-1)(5x+8)=0` `⇔(3x-1)(3x+1-5x-8)=0` `⇔(3x-1)(-2x-7)=0` `⇔` \(\left[ \begin{array}{l}3x-1=0\\-2x-7=0\end{array} \right.\) `⇔` \(\left[ \begin{array}{l}3x=1\\-2x=7\end{array} \right.\) `⇔` \(\left[ \begin{array}{l}x=\frac{1}{3}\\x=-\frac{7}{2}\end{array} \right.\) Vậy `S={(1)/(3);-(7)/(2)}` Trả lời
Đáp án: \(\left[ \begin{array}{l}x=\frac{1}{3}\\x=\frac{7}{2}\end{array} \right.\)
Giải thích các bước giải:
Ta có: a) 9x ²-1=(3x-1)(5x+8)
<=> (3x)²-1² = (3x-1)(5x+8)
⇔ (3x-1) (3x+1) = (3x-1)(5x+8)
⇔ (3x-1) (3x+1) – (3x-1)(5x+8) = 0
⇔ (3x-1) [(3x+1) – (5x+8)] = 0
⇔ (3x-1) (3x+1 – 5x -8) = 0
⇔ (3x-1) ( -2x -7) =0
⇔ \(\left[ \begin{array}{l}3x-1=0\\-2x-7=0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}3x=1\\2x=-7\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=\frac{1}{3}\\x=\frac{7}{2}\end{array} \right.\)
Vậy ………..
CHÚC BẠN HỌC TỐT!
@sakura
#gentleteam
Đáp án + Giải thích các bước giải:
`a//9x^{2}-1=(3x-1)(5x+8)`
`⇔(3x+1)(3x-1)=(3x-1)(5x+8)`
`⇔(3x+1)(3x-1)-(3x-1)(5x+8)=0`
`⇔(3x-1)(3x+1-5x-8)=0`
`⇔(3x-1)(-2x-7)=0`
`⇔` \(\left[ \begin{array}{l}3x-1=0\\-2x-7=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}3x=1\\-2x=7\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=\frac{1}{3}\\x=-\frac{7}{2}\end{array} \right.\)
Vậy `S={(1)/(3);-(7)/(2)}`