Math Is Fun Forum

Karn

Member

Registered: 2009-11-15

Posts: 14

Number and Algebra

Hello

Solve graphically

(a)         (x+3)(x+2)= 10

(b)        -2x^3 + 3x^2 - 1=4

c)          y= 2x+ 3 and x= 2y + 1

What does it mean to 'solve graphically'

Thank you for any help provided.

Anakin

Member

Registered: 2009-10-04

Posts: 145

Re: Number and Algebra

Normally when then the textbook says solve graphically, it means graph it on a graphing calculator or some applet like this: http://www.mathsisfun.com/data/graph.html

And you see for what value of x, y is equal to 0 by looking at the x-intercepts of the graph. That is how you would go about solving it.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Number and Algebra

Hi

For a)

http://www.mathsisfun.com/graph/functio … 6666666667

For b)

http://www.mathsisfun.com/graph/functio … 6666666667

For c)

http://www.mathsisfun.com/graph/functio … =-8&ymax=8

Last edited by bobbym (2009-11-22 19:30:46)

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: Number and Algebra

And you can zoom in to get more accurate values.

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

Karn

Member

Registered: 2009-11-15

Posts: 14

Re: Number and Algebra

Thank you

also

How would yous solve b) without a calculator?

mmdd1823

Member

Registered: 2009-11-23

Posts: 1

Re: Number and Algebra

Can you give more examples to do with statistics?

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Number and Algebra

Hi Karn;

How would yous solve b) without a calculator?

Yes:

The school way is possible here:

Factor it:

-( x + 1 ) ( 2x^2 - 5x + 5 ) = - 2x^3 + 3x^2 - 5 = 0

Last edited by bobbym (2009-11-23 18:48:08)

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Number and Algebra

Hi mmdd1823;

Can you give more examples to do with statistics?

No, root location is used when trying to find the roots of equations. Generally statistics is more concerned with the area under curves than with roots.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.