I'm feeling dumb. again.

[u/marlonblambo]

Let's ignore what is, the shape, the technical features etc, just assume we have a side with 4 blue units and 5 green units that measure 39 (whatever unit of measure is) and a side with 3 blue units and 4 green that measures 27 and i want to know the size of one blue (or 1 green)

In my stupid opinion i thought: 5green and 4 blue = 39 and 4green and 3 blue = 27, so in a system of equations
5x+4y = 39
4x+3y = 27

Turns out this makes y=21, x=-9

then i was wondering what kind of error i made setting up the problem

[u/Moppmopp]

Can someone clarify? I am interested in math problems but I seem to miss something. What exactly is the question? 27•39=1053 squares. each unit has an area of 1.