Question 21540
	GIVEN ORDERED PAIRS (x,y)					
	x	y				
	1	6				
	3	26				
	-2	21				
	y=ax^2+bx+c		substituting the 3 ordered pairs value for x and y in this eqn.we get			
	a+b+c=6		I			
	9a+3b+c=26		II			
	4a-2b+c=21		III	

II-I	8a+2b=20	or	4a+b=10	IV
II-III	5a+5b=5	or	a+b=1	V
IV-V	3a=9	or	a=3	
V	3+b=1	or	b=-2	
I	3-2+c=6	or	c=5	
hence y = 3x^2-2x+5