Question

Thu gọn các đa thức sau:
a) P(x) = −x(x + 5) − (2x − 3) + x^2(3x − 2)
b) Q(x) = 2x(x + 1) + 3x(5 − x) − 7(x − 5).

Answer 1

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

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

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

\(P\left(x\right)=3x^3-3x^2-7x+3\)

b) \(Q\left(x\right)=2x\left(x+1\right)+3x\left(5-x\right)-7\left(x-5\right)\)

\(Q\left(x\right)=2x^2+2x+15x-3x^2-7x+35\)

\(Q\left(x\right)=-x^2+10x+35\)

Answer 2

a: P(x)=-x^2-5x-2x+3+3x^3-2x^2

=3x^3-3x^2-7x+3

b: Q(x)=2x^2+2x+15x-3x^2-7x+35

=-x^2+10x+35