Ricardo throws a stone off a bridge into a river below. The stone's height (in meters above the water), xxx seconds after Ricardo threw it, is modeled by w(x)=-5(x-8)(x+4)w(x)=−5(x−8)(x+4)w , left parenthesis, x, right parenthesis, equals, minus, 5, left parenthesis, x, minus, 8, right parenthesis, left parenthesis, x, plus, 4, right parenthesis How many seconds after being thrown will the stone reach its maximum height? seconds khan