Amir stands on a balcony and throws a ball to his dog, who is at ground level. The ball's height (in meters above the ground), xxx seconds after Amir threw it, is modeled by h(x)=-(x+1)(x-7)h(x)=−(x+1)(x−7)h, (, x, ), equals, minus, (, x, plus, 1, ), (, x, minus, 7, )How many seconds after being thrown will the ball reach its maximum height?