Question

The solutions to 15(2a – 2) = 5(a2 – 1) are:

a = 1, a = –1

a = 5, a = –1

a = 5, a = 1

Answer 1

Solve 15(2a − 2) = 5(a^2 − 1):

Divide both sides by 5: 3(2a − 2) = a^2 − 1 → 6a − 6 = a^2 − 1.

Rearrange: 0 = a^2 − 6a + 5 = (a − 1)(a − 5).

So a = 1 or a = 5.

Therefore the correct choice is: a = 5, a = 1 (equivalently a = 1, a = 5).