Answer:
CD = 4
Step-by-step explanation:
I believe you know the geometric mean for altitudes?
CD = √AD * DB = √8 * 2 = √16 = 4
If you are not aware of this theorem, then use the similarity of triangles.
ADC ~ CDB
AD/DC = CD/DB (cross-multiply)
CD^2 = AD*DB,
CD = √AD * DB = √8 * 2 = √16 = 4
-2/5
Step by Step :
18 - 8 = 10
-15 - 10 = -25
10/-25 = -2/5
If he got 5 points in the first round and he needed at least thirty he would score 9 points in the next three rounds
Answer:

Step-by-step explanation:
simplify
by putting the negative sign on the outside. 
find the LCM of the denominators. It is (x-1)(x-2). Multiply by the LCM:

Simplify:

solve: 