a) \(a^2-2a+1=a^2-2\times a\times1+1^2=\left(a-1\right)^2\)
b) sửa lại đề thành \(1-4x+4x^2\)
\(1-4x+4x^2=1^2-2\times2x\times1+\left(2x\right)^2=\left(1-2x\right)^2\)
c) bạn xem lại đề câu C nha mik làm lun
d) \(25x^2-20xy+4y^2=\left(5x\right)^2-2\times5x\times2y+\left(2y\right)^2=\left(5x-2y\right)^2\)
a) \(a^2-2a+1\)
\(=\left(a-1\right)^2\)
b) Sửa đề \(1-4x+4x^2\)
\(=\left(2x\right)^2-2.2x+1\)
\(=\left(2x-1\right)^2\)
c) \(a^2+9-6x\)
\(=a^2-2.x.3+3^2\)
\(=\left(a-3\right)^2\)
d) \(25x^2-20xy+4y^2\)
\(=\left(5x\right)^2-2.5x.2y+\left(2y\right)^2\)
\(=\left(5x-2y\right)^2\)
a) a2-2a+1 = (a-1)2
b) 1-4x+4x
= 12 -2.2x.1+(2x)2
= (2x+1)2
c) a2+9-6x
= a2-2.3x+32
= (a-3)2
d) 25x2-20xy+4y2
= (5x)2- 2.5x.2y+(2y)2
=(5x-2y)2
a, a2 - 2a + 1= (a-1)2
b, 1 - 4x +4x = (2x +1)2
c, a2 + 9 -6x=(a-3)2
d, 25x2 - 20xy +4y2=(5x-2y)2
