Answer:
[tex]y = 15[/tex]
[tex]AC = 24[/tex]
[tex]DC = 12[/tex]
Step-by-step explanation:
Given
[tex]AD = 12[/tex]
[tex]AC = 4y - 36[/tex]
See attachment
Solving for y
From the attachment:
[tex]AD = DC[/tex]
and
[tex]AC = AD + DC[/tex]
Substitute DC for AD
[tex]AC = AD + AD[/tex]
[tex]AC = 2AD[/tex]
Substitute values for AD and AC
[tex]4y - 36= 2*12[/tex]
[tex]4y - 36= 24[/tex]
Collect Like Terms
[tex]4y = 36+ 24[/tex]
[tex]4y = 60[/tex]
Solve for y
[tex]y = 60/4[/tex]
[tex]y = 15[/tex]
[tex]AC = 4y - 36[/tex]
[tex]AC = 4 * 15 - 36[/tex]
[tex]AC = 24[/tex]
[tex]AD = DC[/tex]
[tex]DC = AD[/tex]
[tex]DC = 12[/tex]