Question

Cho 2 đa thức

P(x)=4x^3+x^2-x+5

Q(x)=2 x^2+4x-1

a)tính P(x)+Q(x)

b)tính P(x)-Q(x)

Answer 1

Giải:

a) \(P(x)+Q(x)=(4x^3+x^2-x+5\text{)}+\left(2x^2+4x-1\right)\)

\(P\left(x\right)+Q\left(x\right)=4x^3+x^2-x+5+2x^2+4x-1\)

\(P\left(x\right)+Q\left(x\right)=4x^3+\left(x^2+2x^2\right)+\left(-x+4x\right)+\left(5-1\right)\)

\(P\left(x\right)+Q\left(x\right)=4x^3+3x^2+3x+4\)

b) \(P(x)-Q(x)=(4x^3+x^2-x+5\text{)}-\left(2x^2+4x-1\right)\)

\(P\left(x\right)-Q\left(x\right)=4x^3+x^2-x+5-2x^2-4x+1\)

\(P\left(x\right)-Q\left(x\right)=4x^3+\left(x^2-2x^2\right)+\left(-x-4x\right)+\left(5+1\right)\)

\(P\left(x\right)-Q\left(x\right)=4x^3-1x^2-5x+6\)

Answer 2

a, \(P\left(x\right)+Q\left(x\right)=4x^3+x^2-x+5+2x^2+4x-1\)

\(P\left(x\right)+Q\left(x\right)=4x^3+\left(x^2+2x^2\right)+\left(-x+4x\right)+\left(5-1\right)\)

\(P\left(x\right)+Q\left(x\right)=4x^3+3x^2+3x+4\)

b, \(P\left(x\right)-Q\left(x\right)=\left(4x^3+x^2-x+5\right)-\left(2x^2+4x-1\right)\)

\(P\left(x\right)-Q\left(x\right)=4x^3+x^2-x+5-2x^2-4x+1\)

\(P\left(x\right)-Q\left(x\right)=4x^3+\left(x^2-2x^2\right)+\left(-x-4x\right)+\left(5+1\right)\)

\(P\left(x\right)-Q\left(x\right)=4x^3-x^2-5x+6\)

Chúc bạn học tốt nha!!!

Answer 3

a) \(P\left(x\right)+Q\left(x\right)=\left(4x^3+x^2-x+5\right)+\left(2x^2+4x-1\right)\)

\(P\left(x\right)+Q\left(x\right)=4x^3+3x^2+3x+4\)

b) \(P\left(x\right)-Q\left(x\right)=\left(4x^2-x^2-x+5\right)-\left(2x^2+4x-1\right)\)

\(P\left(x\right)-Q\left(x\right)=4x^3+\left(x^2-2x^2\right)+\left(-x-4x\right)+\left(5+1\right)\)

\(P\left(x\right)-Q\left(x\right)=4x^3-x^2-5x+6\)