giúp mk

9² - 30xy + 25y²

= ( 3x )² - 2 . 3x . 5y + ( 5y )²

= ( 3x - 5y )²

Sai thì thôi

thank

ko sao

That so easy bài này chệ làm rồi :))))))) mới lớp 7

x4+2x3+3x2+2x+1x4+2x3+3x2+2x+1 

Đặt y=x2+1y=x2+1, ta có : 

A=x4+2x3+3x2+2x+1A=x4+2x3+3x2+2x+1

=x4+2x2+1+x2+2x+2x3=x4+2x2+1+x2+2x+2x3

=(x2+1)2+2x(x2+1)+x2=(x2+1)2+2x(x2+1)+x2 

=y2+2xy+x2=y2+2xy+x2 

=(x+y)2=(x2+x+1)

Mấy bài này that so easy

a) Ta có: \(x^2-2xy+y^2-2x+2y\)

\(=\left(x-y\right)^2-2\left(x-y\right)\)

\(=\left(x-y\right)\left(x-y-2\right)\)

b) Ta có: \(x^2-4x+4-x^2y+2xy\)

\(=\left(x-2\right)^2-xy\left(x-2\right)\)

\(=\left(x-2\right)\left(x-2-xy\right)\)

c) Ta có: \(ax^2-3axy-x^2+6xy-9y^2\)

\(=ax\left(x-3y\right)-\left(x^2-6xy+9y^2\right)\)

\(=ax\left(x-3y\right)-\left(x-3y\right)^2\)

\(=\left(x-3y\right)\left(ax-x+3y\right)\)

d) Ta có: \(2a^2x-5a^2y-4x^2+30xy-25y^2\)

\(=a^2\left(2x-5y\right)-\left(4x^2-30xy+25y^2\right)\)

\(=a^2\left(2x-5y\right)-\left(2x-5y\right)^2\)

\(=\left(2x-5y\right)\left(a^2-2x+5y\right)\)

ab hay là xy bạn ơi

câu này phải ko

\(2x^2-7xy+3y^2+5xz-5yz+2z^2=\left(2x^2+2z^2\right)+\left(5xz-5yz\right)-\left(7xy-3y^2\right)\)

\(=2\left(x^2+z^2\right)+5z\left(x-y\right)-y\left(7x-3y\right)\)

\(2x^2-7xy+3y^2+5xz-5yz+2z^2\)

\(=\left(2x^2+4xz-6xy\right)-\left(xy+2yz-3y^2\right)+\left(2z^2+xz-3yz\right)\)

\(=2x\left(x+2z-3y\right)-y\left(x+2z-3y\right)+z\left(x+2z-3y\right)\)

\(=\left(2x-y+z\right)\left(x+2z-3y\right)\)

ab hay xy bạn

cả hai ab và xy

\(A=4x^2+6x=2x\left(2x+3\right)\)

\(B=\left(2x+3\right)^2-x\left(2x+3\right)=\left(2x+3\right)\left(2x+3-x\right)=\left(2x+3\right)\left(x+3\right)\)

\(C=\left(9x^2-1\right)-\left(3x-1\right)^2=\left(3x-1\right)\left(3x+1\right)-\left(3x-1\right)^2=\left(3x-1\right)\left(3x+1-3x+1\right)=2\left(3x+1\right)\)

\(D=x^3-16x=x\left(x^2-16\right)=x\left(x-4\right)\left(x+4\right)\)

\(E=4x^2-25y^2=\left(2x-5y\right)\left(2x+5y\right)\)

\(G=\left(2x+3\right)^2-\left(2x-3\right)^2=\left(2x+3-2x+3\right)\left(2x+3+3x-3\right)=6.4x=24x\)

\(A=2x\left(2x+3\right)\\ B=\left(2x+3\right)\left(2x+3-x\right)=\left(2x+3\right)\left(x+3\right)\\ C=\left(3x-1\right)\left(3x+1\right)-\left(3x-1\right)^2\\ =\left(3x-1\right)\left(3x+1-3x+1\right)\\ =2\left(3x-1\right)\\ D=x\left(x^2-16\right)=x\left(x-4\right)\left(x+4\right)\\ E=\left(2x-5y\right)\left(2x+5y\right)\\ G=\left(2x+3-2x+3\right)\left(2x+3+2x-3\right)\\ =24x\)

a) \(=x^2-\left(2y\right)^2=\left(x-2y\right)\left(x+2y\right)\)

b) \(=x^2-\left(3y\right)^2=\left(x-3y\right)\left(x+3y\right)\)

c) \(=\left(2x-1\right)^2-\left(2y\right)^2=\left(2x-1-2y\right)\left(2x-1+2y\right)\)

d) \(=x^2-10xy+\left(5y\right)^2=\left(x-5y\right)^2\)

e) \(=\left(3x\right)^2-6x+1=\left(3x-1\right)^2\)

f) \(=\left(5x\right)^2+20x+4=\left(5x+2\right)^2\)

\(a)x^2-4y^2=(x-2y)(x+2y)\\b)x^2-9y^2=(x-3y)(x+3y)\\c)(2x-1)^2-4y^2=(2x-1-2y)(2x-1+2y)\\d) x^2-10xy+25y^2=(x-5y)^2\\e)9x^2-6x+1=(3x-1)^2\\f)25x^2+20x+4=(5x+2)^2\)