Answer:
[tex]4x - 6 = 90 \\ 4x = 96 \\ \boxed{x = 24}[/tex]
Now, AD is an altitude of∆ABC
Therefore, D is the midpoint of BC
[tex]x + 7 = 2x - 15 \\ \boxed{x = 22}[/tex]
CD is (22+7) = 29 & DB is (2×22-15) = 29
[tex] \huge \boxed{\: x = 24 }\\ \huge \boxed{CD \: and \:DB= 29}[/tex]
