Which table shows a proportional relationship between x and y?

The isosceles triangle has two sides of equal length, a, that sre longer than the length of the base ,b. the equation 2a+b=15.7 can be used to find the sides length. if one of the longer sides is 6.3 centimeters what is the length of the base

This is so hard and it’s for a test

Christina can paint 420 square feet in 105 minutes. which unit rate describes the scenario?