Question

Given 4a+2b+c=19, a-b+c=8, -2a+b=0, solve for a,b,c.

Much appreciated :)

Answer 1

since b = 2a (eq. #3), use that to get

8a+c = 19
-a+c = 8
now subtract to get
9a = 11
a = 11/9
now finish it off