First group the coefficients and variables.

– w²(5w⁷) = (– 1 · 5) (w² · w⁷)

=  (– 5) (w² · w⁷)            (Multiply:  – 1 · 5 = –  5)

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

=  (– 5) (w^{2 + 7} )    

=  – 5w⁹                        (Add exponents: 2 + 7 = 9)

Product of  Product of – w²(5w⁷) is – 5w⁹.