Question

According to the closure property, what must be true about the sum of rational numbers ab
and cd
?

Option 1: The sum is rational

Option 2: The sum is irrational

(1 point)
Option

Answer 1

Option 1: The sum is rational.

Reason: If a/b and c/d are rational (a,b,c,d integers, b,d ≠ 0), then
a/b + c/d = (ad + bc)/(bd),
which is a ratio of integers with nonzero denominator, hence rational.