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a/ \(=x^3-2x^5\)
b/\(=5x^2+5-x^3-x\)
c/ \(=x^3+3x^2-4x-2x^2-6x+8=x^3=x^2-10x+8\)
d/ \(=x^2-x^3+4x-2x+2x^2-8=3x^2-x^3+2x-8\)
e/ \(=x^4-x^2+2x^3-2x\)
f/ \(=\left(6x^2+x-2\right)\left(3-x\right)=17x^2+5x-6-6x^3\)
\(1,=3xy\left(x^2+2xy+y^2\right)=3xy\left(x+y\right)^2\\ 2,=7xy\left(2x-3y+4xy\right)\\ 3,=\left(x-1\right)\left(x^2-4\right)=\left(x-2\right)\left(x+2\right)\left(x-1\right)\\ 4,=\left(x-y\right)\left(10x+8\right)=2\left(5x+4\right)\left(x-y\right)\\ 5,=\left(b-c\right)\left(8a-6b\right)=2\left(4a-3b\right)\left(b-c\right)\\ 6,=\left(x-1\right)\left(x^2-16\right)=\left(x-4\right)\left(x+4\right)\left(x-1\right)\\ 7,=x\left(x-y\right)+5\left(x-y\right)=\left(x-y\right)\left(x+5\right)\\ 8,=\left(3x+1-x-1\right)\left(3x+1+x+1\right)=2x\left(4x+2\right)=4x\left(2x+1\right)\\ 9,=\left(2x-3y\right)\left(4x^2+6xy+9y^2\right)\\ 10,=\left(x-1\right)^2-4y^2=\left(x-2y-1\right)\left(x+2y-1\right)\)
1: Ta có: \(\left(x+3\right)\left(x^2-3x+9\right)-\left(x^3+54\right)\)
\(=x^3+27-x^3-54\)
=-27
2: Ta có: \(\left(2x+y\right)\left(4x^2-2xy+y^2\right)-\left(2x-y\right)\left(4x^2+2xy+y^2\right)\)
\(=8x^3+y^3-8x^3+y^3\)
\(=2y^3\)
\(1,=x^3+270-x^3-54=-27\\ 2,=8x^3+y^3-8x^3+y^3=2y^3\\ 3,=x^3-3x^2+3x-1-x^3-8+3x^2-48=3x-57\\ 4,=x^3-x-x^3-1=-x-1\\ 5,=8x^3-5\left(8x^3+1\right)=-32x^3-5\\ 6,=27+x^3-27=x^3\\ 7,làm.ở.câu.3\\ 8,=x^3-6x^2+12x-8+6x^2-12x+6-x^3-1+3x\\ =3x-3\)
a: Ta có: \(3\left(2x-3\right)+2\left(2-x\right)=-3\)
\(\Leftrightarrow6x-9+4-2x=-3\)
\(\Leftrightarrow4x=2\)
hay \(x=\dfrac{1}{2}\)
Bài 2:
a: Ta có: \(A=\left(x+1\right)^3+\left(x-1\right)^3\)
\(=x^3+3x^2+3x+1+x^3-3x^2+3x-1\)
\(=2x^3+6x\)
b: Ta có: \(B=\left(x-3\right)^3-\left(x+3\right)\left(x^2-3x+9\right)+\left(3x-1\right)\left(3x+1\right)\)
\(=x^3-9x^2+27x-27-x^3-27+9x^2-1\)
\(=27x-55\)
1. \(\left(x+2\right)\left(x^2-2x+1\right)\)
= \(x^3-2x^2+x+2x^2-4x+2\)
= \(x^3-3x+2\)
2. \(\left(x-1\right)\left(x^2-x+2\right)=x^3-x^2+2x-x^2+x-2\)
= \(x^3-2x^2+3x-2\)
( mấy ý kia tương tự : nhân lần lượt vào nha e )
A ngại vt ! hì :D
1.(x-2)(x^2-2x+1)
=x^3-2x^2+x-2x^2+4x-2
=x^3-4x^2+5x-2
2.(x-1)(x^2-x+2)
=x^3-x^2+2x-x^2+x-2
=x^3-2x^2+3x-2
3.(x-1)(3-x)
=3x-x^2-3+x
=-x^2+4x-3
4.(x-2)(3-x)
=3x-x^2-6+2x
=-x^2+5x-6
5.(x-1)(x^2-2x+3)
=x^3-2x^2+3x-x^2+2x-3
=x^3-3x^2+5x-3
6.(x^2-3x+1)(x-1)
=x^3-x^2-3x^2+3x+x-1
=x^3-4x^2+4x-1
7.(x^2-2x-1)(x-1)
=x^3-x^2-2x^2+2x-x+1
=x^3-3x^2+x-1
8.(x^2-x+3)(x-3)
=x^3-3x^2-x^2+3x+3x-9
=x^3-4x^2+6x-9
9.(x+1)(-x^2-2x+1)
=-x^3-2x^2+x-x^2-2x+1
=-x^3-3x^2-x+1