Question

15
a2 − 1
=
5
2a − 2

Which equation results from cross-multiplying?




15(a2 – 1) = 5(2a – 2)

15(2a – 2) = 5(a2 – 1)

15(a2 – 1)(2a – 2) = 5(2a – 2)(a2 – 1)

Answer 1

Cross-multiplying gives: 15(2a − 2) = 5(a^2 − 1).

Reason: multiply both sides by (a^2 − 1)(2a − 2) or cross-multiply numerators and denominators: 15·(2a − 2) = 5·(a^2 − 1).