Math questions..please help!!?

Question

here are some questions i need help with..

#1. a rock falls from a tower that is 102.9m high. As it is falling, its height is given by the formula h= 102.9-4.9t^2. How many seconds will it take for the rock to hit the ground (h=0)??

#2.solve the inequality. usa algebra to solve the corresponding equation.

x^2+7>=0

THANK YOU VERY MUCH IN ADVANCE FOR HELPING!!

Answer 1

1. A rock falls from a tower that is 102.9m high. As it is falling, its height is given by the formula h= 102.9-4.9t^2. How many seconds will it take for the rock to hit the ground (h=0)??

Equate h to 0 in the formula.

0 = 102.9 - 4.9t^2

Transpose the constant.

-102.9 = -4.9t^2

Divide by the coefficient of t^2 to both sides.

21 = t^2

Remove the square on the variable.

+/- sqrt(21) = t

t = +4.58, -4.58

Since time cannot be negative, t = 4.58 and the rock will take 4.58s to hit the ground.

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2.solve the inequality. usa algebra to solve the corresponding equation.

x^2+7>=0

Transpose the constant.

x^2 >= -7

Remove the square.

x >= +/- sqrt(-7)

An imaginary number has no real square root.

x >= +/- 7i, where i=sqrt(-1)

Answer 2

1. 6

2. 1412423255453

Answer 3

1.  You are solving for t (time in seconds) when h=0, so set up the equation:

0 = 102.9 - 4.9t²

rewrite:

4.9t² = 102.9

divide both sides by 4.9:

t² = 21

square root both sides:

t = 4.582575695

time is approximately 4.6 seconds

#2) x can be any number because any number squared is positive and when you add seven, obviously it's going to be ≥ 0.

answer:

x = all real numbers

that's it! ;)