# Finding a basis for a subspace

ver_mathstats
Homework Statement:
Find a basis for the subspace in R[SUP]4[/SUP] consisting of the form (a,b,c,d) when c=2a+2b and d=a-5b
Relevant Equations:
c=2a+2b and d=a-5b
I had assumed that we had to put our values into a matrix so I did [1 2 -1 0; 1 -5 0 -1] and then I would do a=[1; 1] and repeat for b, c, and d. This is incorrect however. I also thought that it could be {(1, 2, -1, 0),(1, -5, 0, -1)} however this was not the answer, and I am unsure of what do to next and hints would be appreciated.

Thank you.

I guess I would try this:$$(a,b,c,d) = a(1,0,?,?) + b(0,1,?,?)$$