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PLEASE HELP!! Is the answer 50 seconds???

Guillermo is a professional deep water free diver.
His altitude (in meters relative to sea level), x seconds after diving, is modeled by

g(x)= 1/20x(x - 100)

How many seconds after diving will Guillermo reach his lowest altitude?

Respuesta :

Answer:

Guillermo reach his lowest altitude 50 sec after diving and the lowest altitude is -125 m

Step-by-step explanation:

Let

x -----> the time in seconds

y ----> altitude in meters

we have

[tex]g(x)=\frac{1}{20}x(x-100)[/tex]

[tex]g(x)=\frac{1}{20}x^{2}-5x[/tex]

This is a vertical parabola open upward

The vertex is a minimum

To find out the lowest altitude, find the vertex

Complete the square

Factor the leading coefficient

[tex]g(x)=\frac{1}{20}(x^{2}-100x)[/tex]

[tex]g(x)+125=\frac{1}{20}(x^{2}-100x+2,500)[/tex]

Rewrite as perfect square

[tex]g(x)+125=\frac{1}{20}(x-50)^{2}[/tex]

[tex]g(x)=\frac{1}{20}(x-50)^{2}-125[/tex]

The vertex is the point (50,-125)

therefore

Guillermo reach his lowest altitude 50 sec after diving and the lowest altitude is -125 m (below the sea level)