Bài 1: Phân tích các đa thức sau thành nhân tử
a) x2 - 2xy + 5x – 10y;
b) x(2x - 3y) - 6y2 + 4xy;
c) 8x3 + 4x2 - y2 - y3
a) a3 - a2b - ab2 + b3 ;
b) ab2c3 + 64ab2 ;
c) 27x3y - a3b3y
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(=2xy+5x+4y^2+10y\)
\(=x\left(2y+5\right)+2y\left(2y+5\right)\)
\(=\left(x+2y\right)\left(2y+5\right)\)
\(=2x\left(x+2y\right)+5\left(x+2y\right)=\left(x+2y\right)\left(2x+5\right)\)
=(x^5-5x^2)-(2xy+10y)
=(x^5-5x^2)-(2xy-10y)
=x^2.(x-5)-2y.(x-5)
=(x^2-2y).(x-5)
k nha
\(x^3-5x^2-2xy+10y=x^2\left(x-5\right)-2y\left(x-5\right)=\left(x-5\right)\left(x^2-2y\right)=\left(x-5\right)\left(x-2y\right)\left(x+2y\right)\)
\(=x^2y\left(x-5\right)-2y\left(x-5\right)+0\)
\(=\left(x-5\right)\left(x^2y-2y\right)\)
xong phân tích nốt cái bậc 2 kia để được max điểm :)))
\(x^2-5x+2xy-10y\)
\(=\left(x^2-5x\right)+\left(2xy-10y\right)\)
\(=x\left(x-5\right)+2y\left(x-5\right)\)
\(=\left(x+2y\right)\left(x-5\right)\)
\(a,5x^2y-10xy^2=5xy\left(x-2y\right)\\ b,x^2+2xy+y^2-5x-5y=\left(x+y\right)^2-5\left(x+y\right)=\left(x+y\right)\left(x+y-5\right)\\ c,x^2-6x+8=\left(x^2-2x\right)-\left(4x-8\right)=x\left(x-2\right)-4\left(x-2\right)=\left(x-2\right)\left(x-4\right)\\ d,5x^2-10xy+5y^2-20z^2=5\left(x^2-2xy+y^2-4z^2\right)=5\left[\left(x-y\right)^2-\left(2z\right)^2\right]=5\left(x-y-2z\right)\left(x-y+2z\right)\)
\(a,=\left(x-y\right)\left(x+y\right)-\left(x+y\right)=\left(x+y\right)\left(x-y-1\right)\\ b,=\left(x+y\right)\left(x-5\right)\\ c,=5x^2\left(x-y\right)-10x\left(x-y\right)=5x\left(x-2y\right)\left(x-y\right)\\ d,=x^2-2xy=x\left(x-2y\right)\\ e,=\left(3x-2y\right)\left(9x^2+6xy+4y^2\right)\)
a: x^2+4xy-21y^2
\(=x^2+7xy-3xy-21y^2\)
\(=x\left(x+7y\right)-3y\left(x+7y\right)\)
\(=\left(x+7y\right)\left(x-3y\right)\)
b: \(5x^2+6xy+y^2\)
\(=5x^2+5xy+xy+y^2\)
=5x(x+y)+y(x+y)
=(x+y)(5x+y)
c: \(x^2+2xy-15y^2\)
\(=x^2+5xy-3xy-15y^2\)
=x(x+5y)-3y(x+5y)
=(x+5y)(x-3y)
d: \(x^2-7xy+10y^2\)
\(=x^2-2xy-5xy+10y^2\)
=x(x-2y)-5y(x-2y)
=(x-2y)(x-5y)
a) \(x^2+4xy-21y^2\)
\(=x^2+7xy-3xy-21y^2\)
\(=x\left(x+7y\right)-3y\left(x+7y\right)\)
\(=\left(x+7y\right)\left(x-3y\right)\)
b) \(5x^2+6xy+y^2\)
\(=5x^2+5xy+xy+y^2\)
\(=5x\left(x+y\right)+y\left(x+y\right)\)
\(=\left(5x+y\right)\left(x+y\right)\)
c) \(x^2+2xy-15y^2\)
\(=x^2+5xy-3xy-15y^2\)
\(=x\left(x+5y\right)-3y\left(x+5y\right)\)
\(=\left(x+5y\right)\left(x-3y\right)\)
d) \(x^2-7xy+10y^2\)
\(=x^2-2xy-5xy+10y^2\)
\(=x\left(x-2y\right)-5y\left(x-2y\right)\)
\(=\left(x-5y\right)\left(x-2y\right)\)
\(1,\\ a,=\left(x-y\right)^2-z^2=\left(x-y-z\right)\left(x-y+z\right)\\ b,=a^2\left(a-x\right)-y\left(a-x\right)=\left(a^2-y\right)\left(a-x\right)\\ c,=\left(x-y\right)^2-z\left(x-y\right)=\left(x-y\right)\left(x-y-z\right)\\ d,=x\left(x-2y\right)+t\left(x-2y\right)=\left(x+t\right)\left(x-2y\right)\\ 2,\\ \Rightarrow x^2-4x+4-x^2+9=6\\ \Rightarrow-4x=-7\Rightarrow x=\dfrac{7}{4}\\ 3,\\ a,x^2+2x+2=\left(x+1\right)^2+1\ge1>0\\ b,-x^2+4x-5=-\left(x-2\right)^2-1\le-1< 0\)
a) x2 - 2xy + 5x - 10y
= x(x - 2y) + 5(x - 2y)
= (x + 5)(x - 2y)
b) x(2x - 3y) - 6y2 + 4xy
= x(2x - 3y) + 2y(2x - 3y)
= (x + 2y)(2x - 3y)
c) 8x3 + 4x2 - y2 - y3
= (4x2 - y2) + (8x3 - y3)
= (2x - y)(2x + y) - (2x - y)(4x2 + 2xy + y2)
= (2x - y)(-4x2 - 2xy - y2 + 2x + y)
d) a3 - a2b - ab2 + b3
= a2(a- b) - b2(a - b)
= (a2 - b2)(a - b) = (a - b)2(a + b)
e) ab2c3 + 64ab2
= ab2(c3 + 64)
= ab2(c + 4)(c2 + 4c + 16)
f) 27x3y - a3b3y
= y[27 - (ab)3]
= y(3 - ab)(a2b2 + 3ab + 9)