Maths Problems!!!!!!!!!!!

3x+7>13
3x>13-7
3x>6
x>2

7y-5<23
7y<23+5
7y<28
y<4

4p - 4<2p + 20
4p-2p<20+4
2p<24
p<12

58 - y>7y + 2
58-2>7y+y
56>8y
7>y
y<7

a x 3 x c
=3ac

2p x 3q
=6pq

4t x 2r x5s
=40rst

m x 3m
=3m²

k x k x k
=k³

j x j - 3
=j²-3

17.5% of $240
=$240(17.5%)
=$42

17.5% of $72 , 760
=$72760(17.5%)
=$12733

2009-04-23 11:26:11 補充：
參考資料:http://hk.knowledge.yahoo.com/question/question?qid=7009042300177

3x + 7 > 13
3x > 13-7
3x > 6
x > 2

7y - 5 < 23
7y < 23+5
7y < 28
y < 4

4p - 4 < 2p + 20
4p + 2p < 20 + 4
6p < 24
p < 4

58 - y > 7y + 2
58 - 2 > 7y + y
56 > 8y
7 > y
y < 7

a x 3 x c
= 3ac

2p x 3q
= (2)(p)(3)(q)
= 6pq

4t x 2r x 5s
= (4)(t)(2)(r)(5)(s)
= 40trs

m x 3m
= 3m^2

k x k x k
= k^3

j x j - 3
= j^2 - 3

17.5% of $240
= 240 x 17.5%
= 42

17.5% of 72
= 72 x 17.5%
= 12.6

17.5% of 760
= 760 x 17.5%
= 133

什麼是↓
1 1
1 + 3
2 4