Since base is common, apply the product of powers property: a^m · aⁿ = a^{m + n}.

x² · x² · x¹ = x^{2 + 2 + 1}

= x⁵                            (Add  exponents: 2 + 2 + 1 = 5)

Product of  x² · x² · x¹ is x⁵.