[求助]GWD-21-12

菲菲

Q12:

If x + y + z = 0, x + 2y + 3z = 0, and y ≠ 0, then x/y=

A. -1/2

B.-1/3

C.-1/6

D.1/2

E. 1/3

How come the answer is A?

luoye1

eq 2 - eq 1 => y + 2z = 0 => z = -0.5y, plug that back into eq 1

x + y - 0.5y = 0 => x = -0.5y => x/y = -0.5

A