Answer:
7. Pablo: No necesitas cambiar un cheque. El hotel acepta tarjetas de crédito. Yo voy a usar MI tarjeta de crédito.
8. Pablo: Es una buena idea. Buscamos una casa de cambio. Yo necesito cambiar un cheque de viajero también. Necesito billetes para comprar regalitos para mi mamá/amiga/prima/etc.
Step-by-step explanation:
The sentence describes a situation in which two friends consider passing by a money exchange place in order to get cash money. They do not have to, though, because they can use their credit card instead.
Given this context, the correct verb that complemments the meaning of the locution "a usar" is "voy" , Spanish for the verb 'to go'.