The answer is 3 for x and Y. But I don’t understand how to get that answer

so it's a square which means all of the sides are equal.

that means x+7=3x+1

      subtract 1 from both sides

x + 6 = 3x

      subtract x from both sides

6 = 2x

      divide both sides by 2

3 = x

you can do the same for y

2y - 1 = -3y + 14

    add 3y to both sides

5y - 1 = 14

     add 1 to both sides

5y = 15

      divide both sides by 5

y = 3