Polynomials [復制鏈接]

1. If (x+4)(x-2)=(x-2)(x-3)+A(x-2)+B(x-3) for all values of x, find the values of A and B.

2.If x^3-3x^2+7x-10 全等 (x-2)(ax^2+bx+c), find the values of a, b and c.

3.If A(x+1)^2+B(x+1)+C 全等 3x^2-8x+7, find the values of A,B and C.

吓.......

你爆開晒左右面, 再compare coefficient, 實做到的喎.........

e.g. 3.If A(x+1)^2+B(x+1)+C 全等 3x^2-8x+7, find the values of A,B and C.

LHS= A(x^2 + 2x +1) +Bx +B +C
    = Ax^2 + (2A+B)x + (A+B+C)

So A=3, 2A+B=-8, A+B+C =7
=> A=3, B=-14, C=18

其他的自己試下做

其實全部都係爆開去先再group term
1) 把所有東西放左LHS, D>0
2-3)爆開去先再group term

THX
唔明再問

hei156

引用第4樓eric_ah4於2007-08-22 13:59發表的“”:
hei156 [表情]

SO WHAT