Question

Answer 1

N(x)=x^4-9x^2+4x+x^3-3x^4-28+2x^4-x^3+9x^2

=-28+4x

Answer 2

\(K\left(x\right)+L\left(x\right)-M\left(x\right)\)

\(=\left(x^4-9x^2+4x\right)+\left(x^3-3x^4-28\right)-\left(-2x^4+x^3-9x^2\right)\)

\(=x^4-9x^2+4x+x^3-3x^4-28+2x^4-x^3+9x^2\)

\(=\left(x^4-3x^4+2x^4\right)+\left(x^3-x^3\right)+\left(-9x^2+9x^2\right)+4x-28\)

\(=0+0+0+4x-28\)

\(K\left(x\right)=4x-28\)

Đặt \(K\left(x\right)=0\Rightarrow4x-28=0\Rightarrow4x=28\Rightarrow x=7\)

Vậy K(x) có nghiệm là x = 7