Question

Sabendo que uma curva que representa uma função do segundo grau passa pelos pontos (-3,1), (1,1) e (0,6). Determinar a lei.

Answer 1

f(x)=ax²+bx+c

f(-3)=9a-3b+c=1 
f(1)=a+b+c=1     
f(0)=c=6 <>>>>>>>>>>>>>>>>>>>>>>>>>.

9a-3b+6=1  ==>9a-3b=-5 (i)
a+b+6=1     ==>a+b=-5  ==>(vezes 9)=> 9a+9b=-45 (ii)

(i) -(ii)

-12b=40 ==b=-10/3  <>>>>>>>>>>>>>>>>>>>

a+b=-5
a-10/3=-5
3a-10=-15
a=-5/3 <>>>>>>>>>>>>>>>>>>>>>

f(x)=-5x²/3-10x/3+6  é a resposta