Question

This is very hard, I don't understand.

Answer 1

`4x - 6 = 90 \\ 4x = 96 \\ \boxed{x = 24}`

Now, AD is an altitude of∆ABC

Therefore, D is the midpoint of BC

`x + 7 = 2x - 15 \\ \boxed{x = 22}`

CD is (22+7) = 29 & DB is (2×22-15) = 29

`\huge \boxed{\: x = 24 }\\ \huge \boxed{CD \: and \:DB= 29}`