F.1 MATH

1. 160 degree - remember the hour-hand is at a position nearer the number 4, not at number 3, so it's not 180, but 160 degree.

2. 30=28-[5(2-p)/2]
30=28-5(2-p)/2
30-28=-5(2-p)/2
2=(-10+5p)/2
4=-10+5p
10+4=5p
14=5p
14/5=p
2.8=p
p=2.8
or(the fraction form):
p=2 4/5

3.(x-2)/5-(x+2)/2=4
2(x-2)/10-5(x+2)/10=4
(2x-4)/10-(5x+10)/10=4
(2x-4-5x-10)/10=4
2x-4-5x-10=40
2x-5x=54
-3x=54
x=-18

2010-01-02 14:14:30 補充：
Which one is wrong? And if you know the answer, why do you ask?

1. 180 degree

9______ . ________3

2&3 == What is '÷' ???