graphing calculator - please help sovling quadratic equation

[Cha0s]

i need to find x in x^2+5x-4=0 and other cubic/ quadratic equations. Is there a quick way to do it. (im a complete newb)

THANK YOU EVERYONE FOR your INPUT. I figured out how to do it

 

[HN]

http://www.math.com/students/calculators/source/quadratic.htm

 

[orakle]

[ -b +- sqrt(b^2 - 4ac) ] / 2a

or easier if you have a ti-83 or compatible calculator.. make a program and slap something like this in it:

Menu("Quad:","General",A,"Standard",B)
Lbl A
Prompt A,B,C
((4ac-B^2)/(4A))->K
((-B)/(2A))->H
Goto C
Lbl B
Prompt A,H,K
Goto C
Lbl C
Disp "X="
If ((-K/(A))<0
Then
Disp "NO SOL"
Else
Disp (H+root(-K/A)),(H-root(-K/A))

that should do it. .. just remember to use the actual right arrow (STO->) where i wrote ->

 

[Toastedlightly]

-b / 2a +- root( b^2 - 4ac) / 2a

 

[BigJ]

Graph it, then use the "zeros" option on your calculator.

 

[KingNothing]

x^2 + 5x - 4 = 0 factors into (x - 4) (x - 1) = 0, so x = 4 or 1

 

[minendo]

Stop relying on the internet and a calculator you moron. The quadratic equation is easy enough for cigar smoking monkies to use.

 

[Kalvin00]

Originally posted by: minendo
Stop relying on the internet and a calculator you moron. The quadratic equation is easy enough for cigar smoking monkies to use.

:thumbsup:

 

[Cha0s]

ok, i have TI-83 Plus, where exactly do i start to write that program?

 

[Cha0s]

Originally posted by: orakle22
[ -b +- sqrt(b^2 - 4ac) ] / 2a

or easier if you have a ti-83 or compatible calculator.. make a program and slap something like this in it:

Menu("Quad:","General",A,"Standard",B)
Lbl A
Prompt A,B,C
((4ac-B^2)/(4A))->K
((-B)/(2A))->H
Goto C
Lbl B
Prompt A,H,K
Goto C
Lbl C
Disp "X="
If ((-K/(A))<0
Then
Disp "NO SOL"
Else
Disp (H+root(-K/A)),(H-root(-K/A))

that should do it. .. just remember to use the actual right arrow (STO->) where i wrote ->

where is menu, etc i dont see those buttons

 

[orakle]

PRGM -> NEW

When you hit PRGM while writing a new program you get a menu full of commands you can pick from.

 

[minendo]

Originally posted by: Cha0s
ok, i have TI-83 Plus, where exactly do i start to write that program?

Pull out one of the batteries and press the on button.

This unlocks the advanced programming features.

 

[eigen]

Originally posted by: Cha0s
ok, i have TI-83 Plus, where exactly do i start to write that program?

Let me get this straight you are two dumb to use the quadratics.But smart enough to write a program to solve it?

Just solve it for christ sake.

 

[SaberDicer]

Originally posted by: KingNothing
x^2 + 5x - 4 = 0 factors into (x - 4) (x - 1) = 0, so x = 4 or 1

Right idea but the factoring is off (if you foil -4 x -1 doesnt = -4)
I don't remeber how to factor it right this second though.

 

[Syringer]

Originally posted by: KingNothing
x^2 + 5x - 4 = 0 factors into (x - 4) (x - 1) = 0, so x = 4 or 1

(x-4)(x-1) = x^2 - 5x + 4

Sorry try again.

 

[shilala]

It's either 42 or eleventy beeeeelion.
I'm not exactly sure which, but I've learned that much hangin out here.

 

[Cha0s]

i need to use the calclulator, because the equations are complicated like 3434.34x^2 +53.33x-10^-5=0

 

[minendo]

Originally posted by: Cha0s
i need to use the calclulator, because the equations are complicated like 3434.34x^2 +53.33x-10^-5=0

That doesn't matter. My retarded brother high on meth could still figure it out using the quadratic equation.

 

[eigen]

Originally posted by: Cha0s
i need to use the calclulator, because the equations are complicated like 3434.34x^2 +53.33x-10^-5=0

Dude, No.

 

[BigJ]

Originally posted by: SaberDicer

Originally posted by: KingNothing
x^2 + 5x - 4 = 0 factors into (x - 4) (x - 1) = 0, so x = 4 or 1

Right idea but the factoring is off (if you foil -4 x -1 doesnt = -4)
I don't remeber how to factor it right this second though.

You can't unless you use the quadratic formula. Then it's simple

-5+/- sqrt(25-4*1*-4)
---
2*1

=

-5+/- sqrt(41)
----
2

 

[AFB]

Originally posted by: Cha0s
i need to find x in x^2+5x-4=0 and other cubic/ quadratic equations. Is there a quick way to do it. (im a complete newb)

Enter equation into y=

2nd Calc, Find Zeros

 

[ArmenK]

Originally posted by: amdfanboy

Originally posted by: Cha0s
i need to find x in x^2+5x-4=0 and other cubic/ quadratic equations. Is there a quick way to do it. (im a complete newb)

Enter equation into y=

2nd Calc, Find Zeros

Thats probably the easiest way to do it on the calculator. You can also use the solver (see page 2-8 of your user's manual).

 

[Cha0s]

Originally posted by: amdfanboy

Originally posted by: Cha0s
i need to find x in x^2+5x-4=0 and other cubic/ quadratic equations. Is there a quick way to do it. (im a complete newb)

Enter equation into y=

2nd Calc, Find Zeros

it gives me Left bound ? and i dont see the value

 

[BigJ]

Originally posted by: Cha0s

Originally posted by: amdfanboy

Originally posted by: Cha0s
i need to find x in x^2+5x-4=0 and other cubic/ quadratic equations. Is there a quick way to do it. (im a complete newb)

Enter equation into y=

2nd Calc, Find Zeros

it gives me Left bound ? and i dont see the value

Left bound = left of where it crosses the axis, Right bound = right of where it crosses the axis.

Are you sure you should even be taking this math if you don't know how to use a calculator?

 

[Cha0s]

i need the x, which makes y=0 it gives me x = -1.91... y = .873483...
i never used it before although im a 2nd year math student