Toán Lớp 9: 2$x^{3}$ + 7$x^{2}$ +4x-4=0 tìm x
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 9: 2$x^{3}$ + 7$x^{2}$ +4x-4=0 tìm x
Comments ( 1 )
$2x^3+7x^2+4x-4=0$
$⇒\left(x+2\right)^2\left(2x-1\right)=0$
$⇒x+2=0\quad \mathrm{hoặc}\quad \:2x-1=0$
TH1: $x+2=0$
$⇒x+2-2=0-2$
$⇒x=-2$
TH2: $2x-1=0$
$⇒2x-1+1=0+1$
$⇒2x=1$
$⇒\dfrac{2x}{2}=\dfrac{1}{2}$
$⇒x=\dfrac{1}{2}$
$\text{Vậy x $\in$ {-2 ; $\dfrac{1}{2}$}}$