Phân tích đa thức thành nhân tử
a) \(x^2+5x-6\)
b) \(7x-6x^2-2\)
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a: \(P=x^2-5x+6\)
\(=x^2-2x-3x+6\)
\(=x\left(x-2\right)-3\left(x-2\right)\)
\(=\left(x-2\right)\left(x-3\right)\)
b: \(P=3x^2+14x-5\)
\(=3x^2+15x-x-5\)
\(=3x\left(x+5\right)-\left(x+5\right)\)
\(=\left(x+5\right)\left(3x-1\right)\)
c: \(P=-2x^2-7x-5\)
\(=-\left(2x^2+7x+5\right)\)
\(=-\left(2x^2+2x+5x+5\right)\)
\(=-\left[2x\left(x+1\right)+5\left(x+1\right)\right]\)
\(=-\left(x+1\right)\left(2x+5\right)\)
a: \(-6x^2+7x-2\)
\(=-6x^2+3x+4x-2\)
\(=-3x\left(2x-1\right)+2\left(2x-1\right)\)
\(=\left(2x-1\right)\left(-3x+2\right)\)
b: \(2x^2-5x+2\)
\(=2x^2-4x-x+2\)
\(=2x\left(x-2\right)-\left(x-2\right)\)
\(=\left(x-2\right)\left(2x-1\right)\)
\(a,=7xy\left(x^2-2xy+y^2\right)=7xy\left(x-y\right)^2\\ b,=3x\left(x-y\right)-5\left(x-y\right)=\left(3x-5\right)\left(x-y\right)\\ c,=x^2+3x+4x+12=\left(x+3\right)\left(x+4\right)\)
\(2x^2-7x+5=\left(2x^2-2x\right)-\left(5x-5\right)=2x\left(x-1\right)-5\left(x-1\right)=\left(2x-5\right)\left(x-1\right)\)
\(3x^2+5x+2=\left(3x^2+3x\right)+\left(2x+2\right)=3x\left(x+1\right)+2\left(x+1\right)=\left(3x+2\right)\left(x+1\right)\)
a: \(2x^2-7x+5=\left(x-1\right)\left(2x-5\right)\)
b: \(3x^2+5x+2=\left(x+1\right)\left(3x+2\right)\)
Bài 3:
A(x)⋮B(x)
=>\(3x^2+5x+m\) ⋮x-2
=>\(3x^2-6x+11x-22+m+22\) ⋮x-2
=>m+22=0
=>m=-22
Bài 2:
a: \(2x^3-8x^2+8x\)
\(=2x\left(x^2-4x+4\right)\)
\(=2x\left(x-2\right)^2\)
b: 2xy+2x+yz+z
=2x(y+1)+z(y+1)
=(y+1)(2x+z)
c: \(x^2+2x+1-y^2\)
\(=\left(x+1\right)^2-y^2\)
=(x+1-y)(x+1+y)
Câu 1:
a:\(\left(4x-1\right)\left(2x^2-x-1\right)\)
\(=8x^3-4x^2-4x-2x^2+x+1\)
\(=8x^3-6x^2-3x+1\)
b: \(\left(4x^3+8x^2-2x\right):2x\)
\(=\frac{4x^3}{2x}+\frac{8x^2}{2x}-\frac{2x}{2x}\)
\(=2x^2+4x-1\)
c: \(\left(6x^3-7x^2-16x+12\right):\left(2x+3\right)\)
\(=\left(6x^3+9x^2-16x^2-24x+8x+12\right):\left(2x+3\right)\)
\(=\left\lbrack3x^2\left(2x+3\right)-8x\left(2x+3\right)+4\left(2x+3\right)\right\rbrack:\left(2x+3\right)\)
\(=3x^2-8x+4\)
a: \(P=2x^2-7x+6\)
\(=2x^2-4x-3x+6\)
\(=2x\left(x-2\right)-3\left(x-2\right)\)
\(=\left(x-2\right)\left(2x-3\right)\)
b: \(P=2x^2-7x+3\)
\(=2x^2-6x-x+3\)
\(=2x\left(x-3\right)-\left(x-3\right)\)
\(=\left(x-3\right)\left(2x-1\right)\)
c: \(P=2x^2+9x-5\)
\(=2x^2+10x-x-5\)
\(=2x\left(x+5\right)-\left(x+5\right)\)
\(=\left(x+5\right)\left(2x-1\right)\)
a: \(6x^2-3xy\)
\(=3x\cdot2x-3x\cdot y\)
=3x(2x-y)
b: \(x^2-y^2-6x+9\)
\(=\left(x^2-6x+9\right)-y^2\)
\(=\left(x-3\right)^2-y^2=\left(x-3-y\right)\left(x-3+y\right)\)
c: \(x^2+5x-6\)
=\(x^2+6x-x-6\)
=x(x+6)-(x+6)
=(x+6)(x-1)
đơn giản wá
a) x^2+5x-6
=x^2-x-6x+6
=x(x-1)-6(x-1)
=(x-6)(x-1)
b) 7x-6x^2-2
=-6x^2+7x-2
=6x^2+3x+4x-2
=-3x(2x-1)+2(2x-1)
=(-3x+2)(2x-1)
Vậy đó pạn!!!