Let y = ax²+bx+c then substitute all of orders. we'll be doing equations system.
[tex]a-b+c=0\\c=3\\a+b+c=2[/tex]
Ok we are at this.
Substitute c = 3 into equation 1 and equation 3.
[tex]a-b+3=0\\a-b=-3[/tex]
[tex]a+b+3=2\\a+b=2-3\\a+b=-1[/tex]
then addition and subtract for a-b = 3 and a+b = -1
[tex]a-b=-3\\a+b=-1\\2a=-4\\a=-2[/tex]
Therefore a = -2, substitute a = -2 in a-b+c=0 or a+b+c=2 but i'm doing a-b+c=0 one.
[tex]a-b+c=0\\\\-2-b+3=0\\-b+1=0\\-b=-1\\b=1[/tex]
Therefore b = 1, substitute both a, b and c into y=ax²+bx+c as we get,
[tex]y=-2x^2+x+3[/tex] #
