First, rewrite the expression as:
#(5 * 7 * 6)(a * a * a)(b^9 * b * b)(c * c^9 * c^6) =>#
#210(a * a * a)(b^9 * b * b)(c * c^9 * c^6)#
Next, use this rule of exponents to again rewrite the expression:
#a = a^color(red)(1)#
#210(a^color(red)(1) * a^color(red)(1) * a^color(red)(1))(b^9 * b^color(red)(1) * b^color(red)(1))(c^color(red)(1) * c^9 * c^6)#
Next, use this rule of exponents to complete the evaluation:
#x^color(red)(a) xx x^color(blue)(b) = x^(color(red)(a) + color(blue)(b))#
#210(a^color(red)(1) * a^color(blue)(1) * a^color(geen)(1))(b^color(blue)(9) * b^color(red)(1) * b^color(green)(1))(c^color(red)(1) * c^color(blue)(9) * c^color(green)(6)) =>#
#210a^(color(red)(1)+color(blue)(1)+color(geen)(1))b^(color(blue)(9)+color(red)(1)+color(green)(1))c^(color(red)(1)+color(blue)(9)+color(green)(6)) =>#
#210a^3b^11c^16#
