Angle-A and angle-B are alternate interior angles with parallel lines cut by a transversal. That tells you that the two angles are EQUAL. So you can write
8x + 78 = 2x + 114 ,
and it should all be smooth sailing for you from that point.
5.12% means
5.12/100 = 0.0512 (each year)
PreOwned Vehicle Cost = 31,100
For 5 years simple interest, the value would be:
31100 * 0.0512 * 5 = $7961.6
Total have to pay: 31,100 + 7961.6 = $39,061.6