Question 477012
y = |2x-4|
<pre>
when 2x-4 is positive or zero then y = 2x-4
when 2x-4 is negative then y = -(2x-4)

That is,

when 2x-4 &#8807; 0 then y = 2x-4
when 2x-4 < 0 then y = -(2x-4)

Solve 2x-4 &#8807; 0
        2x &#8807; 4
         x &#8807; 2

Solve 2x-4 < 0
        2x < 4
         x < 2

Therefore 

when x &#8807; 2, then y = 2x-4
when x < 2, then y = -(2x-4)

Normally that is written:

{{{y=system(matrix(2,3,

2x-4, when, x>=2,
-(2x-4), when, x<2))}}} 

And you might want to write -(2x-4) as -2x+4

{{{y=system(matrix(2,3,

2x-4, when, x>=2,
-2x+4, when, x<2))}}} 

Sometimes they put "if" instead of "when"

{{{y=system(matrix(2,3,

2x-4, if, x>=2,
-2x+4, if, x<2))}}}

And sometimes they just put a comma there,

{{{y=system(matrix(2,3,

2x-4, ",", x>=2,
-2x+4, ",", x<2))}}}

Edwin</pre>