# [R] Linear system

Arne Henningsen ahenningsen at email.uni-kiel.de
Wed May 25 15:02:10 CEST 2005

```On Wednesday 25 May 2005 14:30, Jim Gustafsson wrote:
> Dear R-help
>
> I have a problem solving a linear system like
>
> 353a+45b+29c=79
> 45a+29b+3c=5
> 29a+3b+4c=8
>
> Is there any way of doing this in R?

You can write this equation system in matrix form:
M * x = y

with
x = ( a, b, c )
M = ( 353, 45, 29,
45, 29,  3,
29,  3,  4 )
y = ( 79, 5, 8 )

you can solve the system by
x = M^(-1) * y

In R you can do this by
R> M = matrix( c( 353, 45, 29, 45, 29,  3, 29,  3,  4 ),
ncol = 3, byrow = TRUE )
R> y <- c( 79, 5, 8 )
R> x <- solve( M ) %*% y
or
R> x <- solve( M, y )

Arne

> Best Regards
> Jim
>
>
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--
Arne Henningsen
Department of Agricultural Economics
University of Kiel
Olshausenstr. 40
D-24098 Kiel (Germany)
Tel: +49-431-880 4445
Fax: +49-431-880 1397
ahenningsen at agric-econ.uni-kiel.de
http://www.uni-kiel.de/agrarpol/ahenningsen/

```