\(\left(3x-2y\right)^2+4\left(3x-2y\right)+4\\ =\left(3x-2y\right)^2+2.2\left(3x-2y\right)+2^2\\ =\left(3x-2y+2\right)^2\)
Áp dụng HĐT số 1 : \(A^2+2AB+B^2=\left(A+B\right)^2\)
(3\(x\) - 2y)2 + 4.(3\(x\) - 2y) + 4
=(3\(x\) - 2y)2 + 2.2 (3\(x-2y\)) + 22
= (3\(x\) - 2y + 2)2
= (3x - 2y)2 + 2(3x - 2y)2 + 22
= (3x - 2y + 2)2