Question

Answer 1

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

  =3x^2+2x-x^3-3x^2-2x+x^3+3

  =3

Answer 2

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

   =x^3-3x+5x^2-15-x^3+5x^2-3x

   =-6x+10x^2-15

   =-2x(3-5x)-15

Answer 3

bằng 3

Answer 4

lại xem chùa r

Answer 5

Bài 4:

a: Ta có: \(P=x\left(3x+2\right)-x\left(x^2+3x\right)-2x+x^3+3\)

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

=3

b: Ta có: \(Q=\left(x^2-3\right)\left(x+5\right)-x\left(x^2-5x+3\right)\)

\(=x^3+5x^2-3x-15-x^3+5x^2-3x\)

\(=10x^2-6x-15\)

Answer 6

Bài 5: 

a: Ta có: \(2\left(3x-2\right)-3\left(x-2\right)=-1\)

\(\Leftrightarrow6x-4-3x+6=-1\)

\(\Leftrightarrow3x=-3\)

hay x=-1

b: Ta có: \(3\left(3-2x^2\right)+3x\left(2x-1\right)=9\)

\(\Leftrightarrow9-6x^2+6x^2-3x=9\)

\(\Leftrightarrow3x=0\)

hay x=0