# Find Why

GinoJ
Posers and Puzzles 20 Feb '07 21:01
1. 20 Feb '07 21:013 edits
If xy*y + ty +z = 0,

Find y.
2. 20 Feb '07 22:431 edit
Originally posted by GinoJ
If xy*y + ty +z = 0,

Find y.
y= (-t +or- sqrt(t^2-4*x*z))/(2x) -the quadriatic formula

correct?

Edit: I forgot some brackets
3. 20 Feb '07 22:471 edit
The quadratic formula suggests 2 solutions.

(-t - sqrt( t*t - 4*x*z)) / (2* x)
(-t + sqrt( t*t - 4*x*z)) / (2* x)

Derived by making a perfect square in order to remove the square function

x*y*y + t*y + z = 0
y*y + t*y/x + z/x = 0
y*y + t*y/x = -z/x
y*y + t*y/x + t*t/(4*x*x) = t*t/(4*x*x) - z/x
(y + t/(2*x))^2 = t*t/(4*x*x) - z/x
y + t/(2*x) = +- sqrt(t*t/(4*x*x) - z/x)
y + t/(2*x) = +- sqrt((t*t - 4*x*z)/(4*x*x))
y + t/(2*x) = 1/(2*x)*+- sqrt(t*t - 4*x*z)
y= -t/(2*x) +- sqrt(t*t - 4*x*z)/(2*x)
y= (-t +- sqrt(t*t - 4*x*z))/(2*x)
4. 21 Feb '07 01:09
Originally posted by geepamoogle
The quadratic formula suggests 2 solutions.

(-t - sqrt( t*t - 4*x*z)) / (2* x)
(-t + sqrt( t*t - 4*x*z)) / (2* x)

Derived by making a perfect square in order to remove the square function

x*y*y + t*y + z = 0
y*y + t*y/x + z/x = 0
y*y + t*y/x = -z/x
y*y + t*y/x + t*t/(4*x*x) = t*t/(4*x*x) - z/x
(y + t/(2*x))^2 = t*t/(4*x*x) - z/x
y + t/(2*x ...[text shortened]... +- sqrt(t*t - 4*x*z)
y= -t/(2*x) +- sqrt(t*t - 4*x*z)/(2*x)
y= (-t +- sqrt(t*t - 4*x*z))/(2*x)
i don't even know who you are or where your from but i cn tell from your above post that you really really need to get out more and that your single
5. 21 Feb '07 03:17
Originally posted by iraqi insurgent
i don't even know who you are or where your from but i cn tell from your above post that you really really need to get out more and that your single
Perhaps you should stay in a day and study grammar.
6. 21 Feb '07 05:17
Originally posted by GinoJ
If xy*y + ty +z = 0,

Find y.
(x)y*y + (t)y + (z) = 0
m*m = t*t - 4xz
(-t +/- m)/2x=y