If a baseball player hits a baseball from 4 feet off the ground with an initial velocity of 64 feet per second, how long will it take the baseball to hit the ground? use the equation h = −16t2 + 64t + 4.

4.0616 seconds approximately

Step-by-step explanation:

We are looking for how long it takes the ball to hit the ground. h is 0 then.

So we are looking to solve -16t^2+64t+4=0

Divide both sides by -4 to make the numbers a little simpler to work with.

4t^2-16t-1=0

You could aim for completing the square or quadratic formula here.

I'm going for quadratic formula.

a=4

b=-16

c=-1

So the discriminant=b^2-4ac=(-16)^2-4(4)(-1)=16^2+16=16(16+1)=16(17)=272

You could have just put (-16)^2-4(4)(-1) into your calculator.

The quadratic formula says to do:

-b plus or minus square root (discriminant)

                             2 times a

=

16 plus or minus sqrt(272)

                   8

=(approximately)

16 plus or minus 16.4924

                  8

=

16+16.4924                            16-16.4924

            or            

        8                                          8

=

32.4924                                  -0.4924

                or              

     8                                               8

=

4.0616                    or             -0.062

So the baseball hits the ground 4.0616 seconds approximately after the ball has been hit.

b

step-by-step explanation:

the equation of a line in point- slope form is

y - b = m(x - a)

where m is the slope and (a, b) a point on the line

calculate m using the slope formula

m = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (0, 4) and (x₂, y₂ ) = (3, - 5) ← 2 points on the line

m = = = - 3

with m = - 3 and (a, b) = (3, - 5), then

y - (- 5) = - 3(x - 3), that is

y + 5 = - 3(x - 3) → b

-81 -56 -27 0 81

step-by-step explanation: