Question

Vă rog frumos, rapid !​

Answer 1

Răspuns:

Explicație pas cu pas:

intersectia cu OY inseamna x=0

rezulta y=9   A(0,9)

si cu OX y=0

si rezulta

x1=3

x2=1

B(3,0)

C(1,0)

Answer 2

$\displaystyle f:\mathbb{R}\rightarrow \mathbb{R}~;f(x)=3x^2-12x+9\\\\ G_f \cap Oy:~x=0~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~A(0,f(0))\\\\ f(0)=3 \cdot 0^2-12 \cdot 0+9=0-0+9=9~~~~~~~~~~~~~A(0,9)\\\\ G_f \cap Ox:~f(x)=0\\\\ 3x^2-12x+9=0\\\\ \Delta=b^2-4ac;~a=3,~b=-12,~c=9\\\\ \Delta=(-12)^2-4 \cdot 3 \cdot 9=144-108=36 > 0$

$\displaystyle x_1=\frac{-b-\sqrt{\Delta} }{2a} =\frac{-(-12)-\sqrt{36} }{2\cdot 3}=\frac{12-6}{6} =\frac{6}{6}=1 ~~~~~~~~~~~~B(1,0)\\\\x_2=\frac{-b+\sqrt{\Delta} }{2a} =\frac{-(-12)+\sqrt{36} }{2\cdot 3}=\frac{12+6}{6} =\frac{18}{6}=3~~~~~~~~~~C(3,0)$