Tavon has a gift card for $150 that loses $3.50 for each​ 30-day period it is not used. He has another gift card for $130 that loses 3 for each​ 30-day period it is not used. a. Write and solve an equation for the number of​ 30-day periods until the value of the gift cards will be equal. b. What will the value of each card be when they have equal​ value?