Given this system of equations:
I want to write x,y,u,v in terms of a,b,c,d. Is possible?
Take the determinant on the righthand side: it is zero. That means the equations are not independent.
you are asking if a,b,c,d determine x,y,u,v. But clearly u/x = 2a, u/y = 2b, v/x = 2c, and v/y = 2d, so if you know a,b,c,d, you only know the ratios of u and v to x and y. so you could double u and v and x and y, and the same ratios would hold. So a,b,c,d do not determine x,y,u,v.
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