Question

1, tìm n để

a, ( x^3 - 4x^2 +x-n)chia hết (x-4)

b, (4x^3-2x^2 +2x+n) chia hết (2x+1)

c, (x^4 -3x^2+3x-n) chia hết (x-3)

d, (2x^4-4x^3+6x^2-12x+n) chia hết ( x-2)

Answer 1

a: Ta có \(x^3-4x^2+x-n⋮x-4\)

\(\Leftrightarrow x^2\left(x-4\right)+x-4+n+4⋮x-4\)

=>n+4=0

hay n=-4

b: ta có: \(4x^3-2x^2+2x+n⋮2x+1\)

\(\Leftrightarrow4x^3+2x^2-4x^2-2x+4x+2+n-2⋮2x+1\)

=>n-2=0

hay n=2

c: \(\Leftrightarrow x^4-3x^3+3x^3-9x^2+6x^2-18x+21x-63-n+63⋮x-3\)

=>63-n=0

hay n=63