Respuesta :
If you need to expand, you multiply all the terms:
x^2 * x^2 = x^4
x^2 * -4 = -4x^2
4 * x^2 = 4x^2
4 * -4 = -16
And then combine:
x^4 - 4x^2 + 4x^2 - 16
Which becomes:
x^2 - 16
x^2 * x^2 = x^4
x^2 * -4 = -4x^2
4 * x^2 = 4x^2
4 * -4 = -16
And then combine:
x^4 - 4x^2 + 4x^2 - 16
Which becomes:
x^2 - 16