A general system of linear equations is
where a,b,c,d,e,f are constant values.
a)Use elimination to solve for x and y in terms of a,b,c,d,e,f.
b)Are there any values that a,b,c,d,e,f cannot have?
The Attempt at a Solution
For part A, I got x=(e-f)/(a-c), assuming using subtraction for elimination, but in the answers it says x=(de-bf)/(ad-bc). Why are the coefficients of y there?
For part B, I think ad=/=bc because then both equations would cancel out, and it is either the exact same equation or has the same slope but parallel and never intersecting.
for example, 15x+9y & 5x+3y