What values of xxx must be excluded from the domain of dfrac18(x−19)(x+20)\\dfrac{18}{(x - 19)(x + 20)}dfrac18(x−19)(x+20)?
x=19x = 19x=19 only
x=19x = 19x=19 and x=−20x = -20x=−20
x=−19x = -19x=−19 and x=20x = 20x=20
x=0x = 0x=0