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)
how many seconds after being thrown will the ball reach its maximum height?
seconds
i know i literally just posted one a couple minutes ago but, me again t-t

3 seconds

Step-by-step explanation:

To find the highest point, we want to find the vertex of the parabola.  Since the function will be negative, the vertex will represent the highest point.  

To find the vertex we want this equation in vertex form:

y=a(x−h)2+k

and the vertex will be (h,k)

We can expand the equation h(x)=-(x+1)(x-7) to be:

To get the vertex form we need to complete the square.

The vertex form is :

so our vertex is (3,16)

This means the highest point will be 16 when x = 3

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.

the answer is c: divide the arc's degree measure by 360°, then multiply by the circumference of the circle.