Verified Answer :

(Cross Multiply)2a+2b=a-b

a=-3b

if b=1; a=-3

correct answer is -3..

Good Luck..

1=a+b. 2=a-b
a= 2+b
1=2+b+b. a=2-1/2=3/2
-1=2b
b=-1/2

a/b= (3/2)/(-1/2)
= (3/2)(-2/1)
=-3