Toán Lớp 8: $6x^{2}$+x-5=0
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Toán Lớp 8: $6x^{2}$+x-5=0
tìm x giúp mình ạ
Comments ( 2 )
Giải đáp:
x = – 1 ; x = 5/6
Lời giải và giải thích chi tiết:
6x^2 + x – 5 = 0
⇔ 6x^2 + 6x – 5x – 5 = 0
⇔ 6x ( x + 1 ) – 5 ( x + 1 ) = 0
⇔ ( x + 1 ) ( 6x – 5 ) = 0
⇔ \(\left[ \begin{array}{l}x+1=0\\6x-5=0\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=-1\\6x=5\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=-1\\x=\dfrac{5}{6}\end{array} \right.\)
Vậy x = – 1 ; x = 5/6
6x^2+x-5=0
6x^2+6x-5x-5=0
(6x^2+6x)-(5x+5)=0
6x(x+1)-5(x+1)=0
(x+1)(6x-5)=0
⇒\(\left[ \begin{array}{l}x+1=0\\6x-5=0\end{array} \right.\)
⇒\(\left[ \begin{array}{l}x=-1\\{x=5/6}\end{array} \right.\)