 • entries
25
138
• views
25887

# Simultanous equations

It seems somone on this server is very fond of procreational activites.I owuld have posted something in dediction but not allowed to post pornographic materail instead so ...

Simultaneous Equations (Linear)

Recreated from a Revision Book. One presumes there is no copyright on Maths 1. Let us assume that you are asked to solve the following pair of equations

2x = 6 - 4y

-3 - 3y = 4x

We must rearrange both equations such that

ax + by = c

where a,b, and c are numbers

Thus

2. 2x + 4y = 6

-4x -3y =3

(rember you are potentialy swapping numbers from both sides of the equation, so they may become negative and vice versa)

Be sure to label those kwrazy equations!

2x + 4y = 6 (1)

-4x -3y =3 (2)

3. You must 'match' the coefficents of either the X's OR Y 's in both equations . This is done by multiplying either one or both of the equations by a suitable number. A postive may match a negative (its far less problematic than rhesus's anyway)

Therfore if we multiply

2x + 4y = 6 (1)

by 2 we should thus get

4x + 8y = 12 (1)

and you'll notice the 4 of the coefficent of X matches

-4x -3y =3 (2)

(Negative no problem)

Be sure to renumber those kwrazy equations !

4x + 8y = 12 (3)

-4x -3y =3 (4)

3. If the Coefficents are the same (both +ve or both -ve) then SUBTRACT

If the Coefficents are different (one +ve and one -ve) then ADD

The latter rule applies here and thus

(3) + (4) 0x +5y =15

Solve this remaining equation

5y =15 - - > y= 3

4. Now subsitue this value back into equation (1)

2x + 4 x 3 = 6 - - > 2x + 12 = 6 - - > 2x = -6 - - > x = -3

5. Now subsitute both equations back into equation (2) and it should work . If not (Na just try again or ask someone else)

(-4 x -3) -( 3 x 3) = 3

x = -3 , y = 3

Re-edited for clearing confusion.Danke Phantasm lol no i just had spare time to waste before whatever i wanted to watch on telly come Which part you lost on? I actually manged to learn this myself from some website a long time ago. Havent done it in ages but can work it out

##### Link to comment

lol wait you can use this

its great Ok look at

http://www.bbc.co.uk/schools/gcsebitesize/maths/algebra/simultaneoushirev1.shtml

_______________________________________________________________________________________

Its probaley clearer on the link but....

Solve these simultaneous equations and find the values of x and y.

* Equation 1: 2x + y = 7

* Equation 2: 3x - y = 8

As you can see they are already in the format ax +by = c

And also the Y coefficent is already matched up. Since the two coeffiecentsa are different you need to add

Add the two equations to eliminate the ys:

* 2x + y = 7

* 3x - y = 8

* ------------

* 5x = 15

* x = 3

Now you got x =3, put into equation 1 (as i state in the guide above, not in the link. its the same results either way but i like to double check)

Equation 1 ) 2x + y = 7

2 x 3 + y = 7

6 + y = 7

y=1

Equation 2 ) 3x - y = 8

3 x 3 - 1 = 8

It works so

X = 3, Y =1

##### Link to comment

Scroll to the bottom an you 'll see they havent arranged

Equation 1: y - 2x = 1

Equation 2: 2y - 3x = 5

Into the ax +by = c format but you can

Equation 1: -2x +y = 1

Equation 2: -3x +2y = 5

Now if we multipoly equation 1 by 2 to make coefficent of Y to match up

Equation 1: -4x +2y = 2

Equation 2: -3x +2y = 5

This comes to

-x = -3

means

x =3

aubstitue into equation 1

Equation 1: 2 x 3 +y = 1

means

6 + y = 1

rearange to

6 + 1 = y

y = 7

Equation 2: -3x +2y = 5

to check this is correct put both y and x into equation 2

Equation 2: -3 x 2 +2 x 7 = 5

x = 3 , y =7 . same results as the link

(lol sorry ran out of the number of quotes im allowed )

Lol i was only ever good on this part of the course ^^ Hopeless at the graphs/quadractic's

##### Link to comment

OMFG .... I always hate math... blehhh

I loved maths so much i took sn A lelvel in it even though i got all Us in my exams ##### Link to comment

ROFL F25, i was sittin in math today, totally stuck on this, and i whipped out my laptop and started browsing the forums. Stumbled upon this gem, and now i understand!!!

God bless you =F|A= Priest ##### Link to comment

Oops Sorry i thought I'm still in f|a forum for games... OK got it so my browser didn't clean old forum cache I visited last time by accident and talking about math lol well...maths can be fun And rofl val. Hope this works - dont blame me if it dosent, blame the BBC ##### Link to comment

O_O what the hell xD this is so simple solved in an other way xD

2x = 6 - 4y

-3 - 3y = 4x

take first equation and fint the x --> x = 3 - 2y

then substitute in the other equation --> - 3 - 3y = 12 - 8y

solve --> 5y = 15 --> y = 3

substitute in first equation --> 2x = -6 --> x = -3

and that's done i use that method only when i 've got to do whith harder equations, like in analytic geometry when u gotta find common points between two circumferences or parables like this:

x^2 + y^2 + 5x + 6y + 13

x^2 + y^2 + 12x + 7y + 2

in that way u can get rid of squared terms and find x & y ##### Link to comment

O_O what the hell xD this is so simple solved in an other way xD

2x = 6 - 4y

-3 - 3y = 4x

take first equation and fint the x --> x = 3 - 2y

then substitute in the other equation --> - 3 - 3y = 12 - 8y

solve --> 5y = 15 --> y = 3

substitute in first equation --> 2x = -6 --> x = -3

and that's done i like being awkwared ##### Link to comment ×   Pasted as rich text.   Paste as plain text instead

Only 75 emoji are allowed.

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
• Home

• Gallery
• Files

• #### Extra

×
• Create New...

## Important Information

By using this site, you agree to our Terms of Use.