b) \(=\left(x-2\right)^2-2\left(x-2\right)\left(x+3\right)+\left(x+3\right)^2\) (hằng đẳng thức số 2)
\(=\left[\left(x-2\right)-\left(x+3\right)\right]^2\)
\(=\left[x-2-x-3\right]^2\)
\(=\left[-5\right]^2=25\)
a) (x+y)^2−(x−y)^2−2x(2y−x) = \(2xy+2x^2\)
b)(x−2)^2+(x+3)^2−2(x−2)(x+3)
\(=\left[\left(x-2\right)-\left(x+3\right)\right]^2=\left(-5\right)^2=25\)
Chúc bạn học tốt!!
a)\(=\left(x^2+2xy+y^2\right)-\left(x^2-2xy+y^2\right)-\left(4xy-2x^2\right)\)
\(=x^2+2xy+y^2-x^2+2xy-y^2-4xy+2x^2\)
\(=2x^2\)
