Hello, I'm studying for the GRE and i'm trying to figure out how (1/b-1/a)=(a-b/ab). If anyone can demonstrate the steps of how these two expressions are identical I would greatly appreciate it. Thanks.
No, no one can explain "how these two expressions are identical" because they are not! What is true is that 1/b- 1/a= (a- b)/ab. To do that, get "common denominators" in the two fractions: (a/a)(1/b)- (b/b)(1/a)= a/ab- b/ab= (a- b)/ab.