Ptich đa thức thành nhân tử a) a2b - 4ab3
b) x8 + 4y4
c) x2 - 10x - 16y2 + 25
mn giúp mình với mình đang cần gấp
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Bài khó quá
4x⁴+4x-3= (2x)²+2(2x)+1-4
=(2x+1)²-2²=(2x+1-2)(2x+1+2)
=(2x-1)(2x+3)
\(\dfrac{xy}{2}-x+\dfrac{x^2}{4}=x\left(\dfrac{y}{2}-1+\dfrac{x}{4}\right)\)
1/(x+2)2 -(3x-1)2=(x+2+3x-1)(x+2-3x+1)=4x(-2x+3)=-8x2+12x
2/(x4+x2)(-2x3-2x)=x2(x2+1)-2x(x2+1)=(x2+1)(x2-2x)
a) x2 ( x+ 2y) -x -2y
= x2 ( x+ 2y) -(x+2y)
= (x2-1)(x+2y)
= (x-1)(x+1)(x+2y)
b)3x2- 3y2 -2 (x-y)2
= 3(x2-y2) -2 (x-y)2
= 3(x-y)(x+y)-2(x-y)(x-y)
\(=\left(x-y\right)\left[3\left(x+y\right)-2\left(x-y\right)\right]\\ =\left(x-y\right)\left(3x+3y-2x+2y\right)\\ =\left(x-y\right)\left(x+5y\right)\)
c) x2- 2x-4y2 - 4y
= (x2-4y2)-(2x+4y)
\(=\left(x-2y\right)\left(x+2y\right)-2\left(x+2y\right)\\ =\left(x+2y\right)\left(x-2y-2\right)\)
d) x3 - 4x2 - 9x +36
= (x3+3x2)-(7x2+21x)+(12x+36)
= x2(x+3)-7x(x+3)+12(x+3)
=(x2-7x+12)(x+3)
\(=\left[\left(x^2-3x\right)-\left(4x-12\right)\right]\left(x+3\right)\\ =\left[x\left(x-3\right)-4\left(x-3\right)\right]\left(x+3\right)=\left(x-4\right)\left(x-3\right)\left(x+3\right)\)
Mình nghĩ là đề thiếu đó bạn :)
đề đáng lẽ phải là: \(x^7+x^2+1\)
\(x^7+x^2+1=\left(x^7-x\right)+\left(x^2+x+1\right)\)
\(=x\left(x^6-1\right)+\left(x^2+x+1\right)\)
\(=x\left(x^3-1\right)\left(x^3+1\right)+\left(x^2+x+1\right)\)
\(=x\left(x-1\right)\left(x^2+x+1\right)\left(x^3+1\right)+\left(x^2+x+1\right)\)
\(=\left[x\left(x-1\right)\left(x+3\right)+1\right]\left(x^2+x+1\right)\)
\(=\left[\left(x^2-x\right)\left(x^3+1\right)+1\right]\left(x^2+x+1\right)\)
\(=\left(x^5-x^4-x^2-x+1\right)\left(x^2+x+1\right)\)
\(\left(x-4\right)^2=x^2-8x+16\)
\(4x^2-6xy+10x^3=2x\left(2x-3y+5x^2\right)\)
Phân tích đa thức sau thành nhân tử:
M=(a^2+b^2-c^2)^2 - 4a^2b^2
Giúp mình với nha! Mình đang cần gấp
\(M=\left(a^2+b^2-c^2\right)^2-4a^2b^2\)
\(=\left(a^2+b^2-c^2\right)^2-\left(2ab\right)^2\)
\(=\left(a^2+b^2-c^2-2ab\right)\left(a^2+b^2-c^2+2ab\right)\)
\(=\left(\left(a^2-2ab+b^2\right)-c^2\right)\left(\left(a^2+2ab+b^2\right)-c^2\right)\)
\(=\left(\left(a-b\right)^2-c^2\right)\left(\left(a+b\right)^2-c^2\right)\)
\(=\left(a-b-c\right)\left(a-b+c\right)\left(a+b-c\right)\left(a+b+c\right)\)
a) \(a^2b-4ab^2\)
\(=ab\left(a-4b\right)\)
b) \(x^8+4y^4\)
\(=\left(x^4\right)^2+\left(2y^2\right)^2\)
\(=\left(x^4-2y^2\right)\left(x^4+2y^2\right)\)
c) \(x^2-10x-16y^2+25\)
\(=\left(x^2-10x+25\right)-16y^2\)
\(=\left(x-5\right)^2-\left(4y\right)^2\)
\(=\left[\left(x-5\right)+4y\right]\left[\left(x-5\right)-4y\right]\)
\(=\left(x-5+4y\right)\left(x-5-4y\right)\)