Question

14.2 Решите уравнения f (x)=0 б и г

Answer 1

Ответ:

14.2.

$b)\ \ f(x)=3x^2-4x\ \ ,\ \ f(x)=0\\\\3x^2-4x=0\ \ ,\ \ \ x\, (3x-4)=0\ \ \Rightarrow \ \ \ x_1=0\ \ ,\ \ \ x_2=\dfrac{4}{3}=1\dfrac{1}{3}\\\\\\d)\ \ f(x)=-0,5x^2-4x+0,1\ \ ,\ \ \ f(x)=0\\\\-0,5x^2-4x+0,1=0\ \Big|\cdot (-10)\\\\5x^2+40x-1=0\ \ ,\ \ \ D/4=20^2-5\cdot (-1)=405\ ,\\\\x_1=\dfrac{-20-\sqrt{405}}{5}=\dfrac{-20-9\sqrt5}{5}\ \ ,\ \ \ x_2=\dfrac{-20+9\sqrt5}{5}$