多项式f(x)被x^2-x-2除时,馀式是-x-5当f(x)被x^2-5x+6除时,馀式是2x+1

求当f(x)被x^2-2x-3除的馀式要过程
2025-06-20 17:07:16
推荐回答(1个)
回答1:

x^2-x-2 =(x-2)(x+1)

f(x) = p(x) .(x^2-x-2) + (-x-5)

f(2) = -2 -5 = -7

f(-1) = 1-5 = -4

x^2-5x+6 =(x-2)(x-3)

f(x) = m(x) .(x^2-5x+6) + (2x+1)

f(2) = 2(2) +1 =5

f(3) = 2(3) +1 = 7

x^2-2x-3 = (x-3)(x+1)

当f(x)被x^2-2x-3除的馀式 = ax+b

f(x) = n(x) .(x^2-2x-3) + (ax+b)

f(3) = 3a+b = 7                                     (1)

f (-1) = -a+b=-4                                    (2)

(1)-(2)

4a=11

a=11/4

from (1)

3a+b = 7  

33/4+b=7

b= -5/4

ie

f(x)被x^2-2x-3除的馀式 = (11/4)x -5/4