Let a(x) be the amount of money remaining on hillary's gift card after purchasing x apps on her phone. a(x)=50-1.25x so, a(12) = this means 38 purchasing 12 apps has 12 new apps 35 purchasing 35 apps has $35 left 65 spending $35 has 35 new apps 15 spending $12 has $12 left

Given ⇒⇒⇒ a(x)=50-1.25x
a(x) be the amount of money remaining on Hillary's gift card.

x number of apps purchased on her phone


∴ a(12) = 50 - 1.25 * 12 = 35

Which mean : She have amount of total money = 50

she purchased 12 apps costs 12 *1.25 = 15 . So , she spent 15

The remaining on Hillary's gift card = 50 - 15 = 35

The correct answer is :

a(12) =35 .

This means that purchasing 12 apps , Hillary has $35 left