Answer:
The ball will be 84 feet above the ground 1.125 seconds and 4.5 seconds after launch.
Step-by-step explanation:
Statement is incorrect. Correct form is presented below:
<em>The height </em>
<em> of an ball that is thrown straight upward from an initial position 3 feet off the ground with initial velocity of 90 feet per second is given by equation </em>
<em>, where </em>
<em> is time in seconds. After how many seconds will the ball be 84 feet above the ground. </em>
We equalize the kinematic formula to 84 feet and solve the resulting second-order polynomial by Quadratic Formula to determine the instants associated with such height:

(1)
By Quadratic Formula:

,
The ball will be 84 feet above the ground 1.125 seconds and 4.5 seconds after launch.
Answer:
The volume of the prism is 
Step-by-step explanation:
we know that
The volume of the prism is equal to

where
B is the area of the triangular base
L is the length of the prism
we have

<em>Find the area of the base B</em>
The area of a equilateral triangle is equal to


substitute

Answer:
x = 6
Step-by-step explanation:
we can multiply the entire equation by 3 to simplify the numbers
-2x + 27 = 4x - 9
27 = 6x - 9
36 = 6x
x = 6