What values of xxx must be excluded from the domain of dfrac19(x−20)(x+21)\\dfrac{19}{(x - 20)(x + 21)}dfrac19(x−20)(x+21)?
x=−20x = -20x=−20 and x=21x = 21x=21
x=20x = 20x=20 only
x=0x = 0x=0
x=20x = 20x=20 and x=−21x = -21x=−21