Answer:
[tex]13x - 4 = 8x + 11 \\ 13x - 8x = 4 + 11 \\ 5x = 15 \\ \frac{5x}{5} = \frac{15}{5} \\ x = 3[/tex]
NOW LET'S FIND THE VALUE OF AD
[tex]ad \: \: length = 13x - 4 \\ \\ x = 3 \\ \\ 13x - 4 \\ 13 \times 3 - 4 \\ 39 - 4 \\ = 35[/tex]