Update 700-math-m3scale.markdown

Author: Joe7M

_build/reference/700-math-m3scale.markdown

@@ -2,10 +2,30 @@
 
 > M3SCALE BYREF m3x3, x, y, Sx, Sy
 
-Scale matrix.
+Multiply the given matrix by a scale matrix. Sx and Sy are the scaling factors in x and y direction.
 
 ```
-| Sx  0  0|
-| 0  Sy  0|
-| *   *  1|
+         | Sx  0  0|
+MScale = | 0  Sy  0|
+         | 0   0  1|
 ```
+
+```
+DIM M(2,2)
+
+Rectangle = [-1,-1, 1,-1, 1,1, -1,1, -1,-1]  ' Create a rectangular polygon
+
+M3IDENT M                                    ' Create Identity Matrix
+
+M3Trans M, 100,100                           ' Move rectangle to position (100,100) 
+M3SCALE M, 0, 0, 50, 50                      ' Scale rectangle by factor 50 in x and y
+M3ROTATE M, 45*pi/180                        ' Rotate by 45°
+
+M3APPLY M, Rectangle                         ' Transform the rectangle
+
+DRAWPOLY Rectangle
+```
+
+M3TRANS, M3SCALE and M3ROTATE perform a matrix multiplication. When performing matrix multiplication, then last matrix is applied first.
+In the example above, the rectangle is first rotated, then scaled and in the last step translated. If the order is changed, the outcome might
+be different.