Look for y:
[tex]AC = DF[/tex]
[tex]2y - 1 = 20[/tex]
[tex]2y = 20 + 1[/tex]
[tex]2y = 21[/tex]
[tex]y = 10.5[/tex]
Look for x:
[tex]BC = EF[/tex]
[tex]x + 9 = y + 8[/tex]
[tex]x + 9 = 10.5 + 8[/tex]
[tex]x + 9 = 18.5[/tex]
[tex]x = 18.5 - 9[/tex]
[tex]x = 9.5[/tex]
Look for AC:
[tex]AC = 2y - 1[/tex]
[tex]AC = 2(10.5) - 1[/tex]
[tex]AC = 21 - 1[/tex]
[tex]AC = 20[/tex]
Look for BC:
[tex]BC = x + 9[/tex]
[tex]BC = 9.5 + 9[/tex]
[tex]BC = 18.5[/tex]
[tex]EF = y + 8[/tex]
[tex]EF = 10.5 + 8[/tex]
[tex]EF = 18.5[/tex]