\(\left(x-2\right)^2-\left(x+2\right)^2\\ =\left[\left(x-2\right)-\left(x+2\right)\right]\left[\left(x-2\right)+\left(x+2\right)\right]\\ =\left(x-2-x-2\right)\left(x-2+x+2\right)\\ =-4.\left(2x\right)\\ =-8x\)
`= x^2 - 4x + 4 - x^2 - 4x - 4`
`= -8x`