+0

# matrix prt. 2

0
407
4
+266

?

Jan 7, 2016

#4
+10

Hi Coldplay,

A matrix is an array of numbers.

It is used a lot to solve difficult simultaneous equations where there is more than 2 unknowns.

If there are 2 unknowns you need 2 equations

If there are 3 unknowns you need 3 equations.

The coefficients of the letters (pronumerals) are the numbers that go into the array.

Have a look at this introduction

http://www.mathsisfun.com/algebra/matrix-introduction.html

Jan 7, 2016

#1
+4079
+5

What is Matrix?!?!?!?!!!!

Jan 7, 2016
#2
+111435
+6

-5x - y  = 21    →      y  = -21 - 5x     (1)

3x - 4y + 5z  = - 8    (3)

-3x - z  = 12   →       z = -3x -12  (2)

Substituting  (1) and (2)  into  (3), we have

3x - 4(-21 - 5x) + 5(-3x -12)   = - 8      simplifiy

3x + 84 + 20x - 15x - 60  = -8

8x  + 24  = -8    subtract 24 from both sides

8x =  - 32     divide both sides by  8

x = -4

And using (1)   y   = -21 - 5(-4)   =   -21 + 20   = -1

And using (2)    z   = -3(-4) - 12   =     12 - 12  = 0

So    (x, y, z)   =  (-4 , -1 , 0)

Jan 7, 2016
#3
+111435
+4

Note, Paypay.......we could have used Gaussian Elimination to solve this....but......I don't know if you have covered that, or not.......also.......it's kind of tedious......!!!!!

I just went the Algebra route........!!!!

Jan 7, 2016
#4
+10

Hi Coldplay,

A matrix is an array of numbers.

It is used a lot to solve difficult simultaneous equations where there is more than 2 unknowns.

If there are 2 unknowns you need 2 equations

If there are 3 unknowns you need 3 equations.

The coefficients of the letters (pronumerals) are the numbers that go into the array.

Have a look at this introduction

http://www.mathsisfun.com/algebra/matrix-introduction.html

Guest Jan 7, 2016