which of the following pairs of expressions are equivalent?

-5(a-1) and -5.a-5
or
12.t+6 and 12(t+1/2)
or
8.c+40 and 8(c-5)
or
6(y+3) and 6.y+3

The pairs of expressions that are equivalent are:

-5(a-1) and -5.a-5

12.t+6 and 12(t+1/2)

6(y+3) and 6.y+3