Math Is Fun Forum

Kurtz

Member

Registered: 2007-10-01

Posts: 27

Quadratics

1. I do not know how to find the equation using the given, x intercept -6 and y intercept √2..

2. P = -t^2 + 26t +106 where 1 ≤ x ≤ 13
         After approx. how many days will 250 people have caught the flu?

Do I just plug in days to find out the approx.? or is there a definite computation?

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I am a mathemagician. You ask why? I point up

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Quadratics

For 2, you want to find t when P=250.

So you have 250 = -t² + 26t + 106
-t² + 26t - 144 = 0

This is a quadratic equation which factorises nicely.
Solve it and choose the value of t that falls within your range.

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Why did the vector cross the road?
It wanted to be normal.

Anakin

Member

Registered: 2009-10-04

Posts: 145

Re: Quadratics

Not sure if this is correct but here it goes for #1:

Back into the equation.

I graphed it and it seemed to suit your description. Hopefully, someone can correct any mistakes I made.

Last edited by Anakin (2009-10-11 08:45:20)