Atrip to portland, oregon, from boston will take 73⁄4 hours. assuming we are two-thirds of the way there, how much longer, in hours, will the trip take?

If we are already two thirds of the way there, there is still (one minus two thirds) one thirds of the way still to go. Providing we're moving at the same speed throughout the entire journey, we will take one third of 73/4 hours to get to Boston.
One third of 73/4 hours
=⅓ x 73/4 hours
=73/12 hours
=6 1/12 hours
Or 6 hours 1/12 of 60 minutes
=6 hours 5 minutes
Or 365 minutes to reach Boston.

for 5x + 4y = 13 is x=13/5 and y=13/4 and for 2x - 5y = -8​ is x=-4 snd y=8/5