Question

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

Q(x) = \(3x-x^2+5\)

Tính :

a) P(x)+Q(x)

b) P(x)-Q(x)

Answer 1

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

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

Answer 2

a,

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

= \(2x^3+x-3x^2-1+3x-x^2+5\)

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

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

b,

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

= \(2x^3+x-3x^2-1-3x+x^2-5\)

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

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

Answer 3

a)

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

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

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

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

b)

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

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

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

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

Chúc bạn học tốt!

Answer 4

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

=\(2x^3+x-3x^2-1+3x-x^2+5\)

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

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

b)

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

=\(2x^3+x-3x^2-1-3x+x^2-5\)

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

=\(2x^3-2x^2-2x-6\)

Chúc bạn họ tốt nha