Arock is dropped from a bridge 320 feet above the river. the pathway that the rock takes can be modeled by the equation h= -16t2+320. how long will it take the rock to reach the river?

4.47 seconds.

Step-by-step explanation:

Hi, the rock will reach the river when the height (h) is 0.

So, replacing in the equation given:

h= -16t2+320

Where t is the time  

0= -16t2+320

Solving for t

-320 = -16t2

-320/-16 =t2

20 = t2

√20 =t

4.47 = t

Assuming that t is the time in seconds, the rock will reach the river after 4.47 seconds.

Feel free to ask for more if needed or if you did not understand something.

no

step-by-step explanation:

2-7=-5

7-2=5

when you combing like terms for ech expression, 5 and -5. these numbers are not equal to each other.

1. x> -5

2. x< 8

step-by-step explanation:

1. 2x> -10

divide by 2 from both sides of equation.

2x/2> -10/2

simplify, to find the answer.

-10/2=-5

x> -5 is the correct answer.

2. 3x< 24

divide by 3 from both sides of equation.

3x/3< 24/3

simplify, to find the answer.

24/3=8

x< 8 is the correct answer.

i hope this you, and have a wonderful day!