Toán Tìm x biết: $x^{2}$ -25-(x+5)=0 Mik đang cần gấp lắm 06/12/2021 By Quinn Tìm x biết: $x^{2}$ -25-(x+5)=0 Mik đang cần gấp lắm
`x^2-25-(x+5)=0` `⇔(x^2-5^2)-(x+5)=0` `⇔(x-5)(x+5)-(x+5)=0` `⇔(x+5)(x-5-1)=0` `⇔(x+5)(x-6)=0` `⇔` \(\left[ \begin{array}{l}x+5=0\\x-6=0\end{array} \right.\)`⇔` \(\left[ \begin{array}{l}x=-5\\x=6\end{array} \right.\) `text{ Vậy x }` `∈{-5;6}` Trả lời
Hướng dẫn trả lời: `x^2-25-(x+5)=0.` `⇒(x^2-5^2)-1.(x+5)=0.` `⇒(x-5).(x+5)-1.(x+5)=0.` `⇒(x+5).[(x-5)-1]=0.` `⇒(x+5).(x-5-1)=0.` `⇒(x+5).(x-6)=0.` $\text{⇒\(\left[ \begin{array}{l}x+5=0.\\x-6=0.\end{array} \right.\)}$ $\text{⇒\(\left[ \begin{array}{l}x=-5.\\x=6.\end{array} \right.\)}$ $\text{Vậy x = -5 hoặc x = 6.}$ Trả lời
`x^2-25-(x+5)=0`
`⇔(x^2-5^2)-(x+5)=0`
`⇔(x-5)(x+5)-(x+5)=0`
`⇔(x+5)(x-5-1)=0`
`⇔(x+5)(x-6)=0`
`⇔` \(\left[ \begin{array}{l}x+5=0\\x-6=0\end{array} \right.\)`⇔` \(\left[ \begin{array}{l}x=-5\\x=6\end{array} \right.\)
`text{ Vậy x }` `∈{-5;6}`
Hướng dẫn trả lời:
`x^2-25-(x+5)=0.`
`⇒(x^2-5^2)-1.(x+5)=0.`
`⇒(x-5).(x+5)-1.(x+5)=0.`
`⇒(x+5).[(x-5)-1]=0.`
`⇒(x+5).(x-5-1)=0.`
`⇒(x+5).(x-6)=0.`
$\text{⇒\(\left[ \begin{array}{l}x+5=0.\\x-6=0.\end{array} \right.\)}$
$\text{⇒\(\left[ \begin{array}{l}x=-5.\\x=6.\end{array} \right.\)}$
$\text{Vậy x = -5 hoặc x = 6.}$