Question

What must be true about a/b
if c/d
and ad+bc/bd
are both rational numbers? Enter 1 for option 1 and 2 for option 2.

Option 1: a/b
is rational

Option 2: a/b
is irrationa

Answer 1

1

Because (ad+bc)/(bd) = a/b + c/d. If c/d and a/b + c/d are rational, then their difference a/b = (a/b + c/d) - c/d is rational.