Jawabanmu

2014-06-12T16:26:11+07:00
Titik (1,2) ------------> 2=a(1)² +b(1) +c
Titik (2,4) ------------> 4 = a(2)² +b(2) +c
Titik (3,8) ------------> 8 = a(3)² + b(3) + c

=> a + b + c =2         
     4a + 2b + c =4
     9a + 3b + c = 8

eliminasi
4a + 2b + c =4
a + b + c =2          =====Dikurangi======

= 3a + b = 2

eliminasi 2
9a + 3b + c = 8
4a + 2b + c =4

= 5a + b = 4

ELiminasi 3
5a + b = 4
3a + b = 2
 2a = 2
a = 1
Substitusi a = 1 ke 3a + b = 2
3(1) + b = 2
b = -1
SUbstitusi a=1, b= -1, ke a+b+c =2
1 + (-1) + c =2
c =2

Persamaan = ax² bx + c ---> x² -x + 2