how do I solve this:
my set up:
10x + 4y + 20z =2.5
7.5x + 6y + 15z = 3
15x + 3y + 40z = 1.75
how to solve this system
There are LOTS of ways.
System of linear equations - Wikipedia, the free encyclopedia
Might it be useful first to confirm that this system is appropriate to the word problem which generated it...?