中一數學正負數問題(今日要) 10點.

1. +3 1/4 - (+21/2 - 1/-2) ÷ -1/4
= +3 1/4 - (+11) ÷ -1/4
= +3 1/4 + 44
= + 47 1/4
2. (+5/7) x (-22/15) - (5/6) x (-9/20)
= (-22/21) - (-3/8)
= -113/168
3. (-3/4) x (-1/4) x (-7/8) ÷ (-7/16)
= (-3/4) x (-1/4) x (-7/8) x (16/-7)
= 3/2
4. (+3)×(-3×-5)- 2×〔(+3)×(-5)〕 _ (+3)×(-3)
----------------------------------------- ---------------
+5 - (-6 ) + ( +3 ) -5

= (+3) x (+15) - 2 x (-15) - (-9)
--------------------------------------
+5+6+3-5

= (+45) + 30 +9
--------------------
9

= 84/9
= +9 1/3

敢就ok la!

add 油!x N

希望你明!

2011-07-24 15:00:16 補充：
我1X years la!

1) +3 1/4 - (+2 1/2 - 1/-2 )÷ -1/4
=3 1/4 -3÷ -1/4
=3 1/4 +0.75
=4

2) (+5/7) × (-22/15) - (5/6) × (-9/20)
=-1 1/21-(-3/8)
=-112/168

3) (-3/4) × (-1/4) × (-7/8) ÷ (-7/16)
=3/16 × (-7/8) ÷ (-7/16)
=-21/128÷ (-7/16)
=3/8


4) (+3)×(-3×-5)- 2×〔(+3)×(-5)〕 _ (+3)×(-3)
----------------------------------------- ---------------
+5 - (-6 ) + ( +3 ) -5

=45+30+9)/9
=84/9
=9/1/3

1. +3 1/4 - (+2 1/2 - 1/-2 ) ÷ -1/4
= +3 1/4 - 2 ÷ -1/4
= +1 1/4 ÷ -1/4
= +1 1/4 x - 4
= - 5
2. (+5/7) x (- 22/15) - (5/6) x (- 9/20)
= (- 22/21) - (- 3/8)
= (- 176/168) - (- 63/168)
= -113/168
3. (-3/4) x (-1/4) x (-7/8) ÷ (-7/16)
= (-3/16) x (-7/8) x (16/-7)
= (21/128) x (16/-7)
= (336/-896)
= (3/-8)
4. (+3)×(-3×-5)- 2×〔(+3)×(-5)〕 _ (+3)×(-3)
---------------------------------------
+5 - (-6 ) + ( +3 ) -5
75 -(-9)
= ----
9
1
= 9 ----
3

2011-07-20 16:18:20 補充：
4. (+3)×(-3×-5)- 2×〔(+3)×(-5)〕 _ (+3)×(-3)
---------------------------------------
+5 - (-6 ) + ( +3 ) -5

1
= 9 ----
3

2011-07-20 16:18:59 補充：
4. (+3)×(-3×-5)- 2×〔(+3)×(-5)〕 _ (+3)×(-3)
---------------------------------------
+5 - (-6 ) + ( +3 ) -5


= 9 1/3

1) +3 1/4 - (+2 1/2 - 1/-2 )÷ -1/4
=3 1/4 - (2 1/2 + 1/2)÷ -1/4
=3 1/4 + (2 1/2 + 1/2)÷ 1/4
=3 1/4 + 4(2 1/2 + 1/2)
=3 1/4 + 4(3)
=15 1/4
2) (+5/7) × (-22/15) - (5/6) × (-9/20)
=-(5/7 x 22/15) + (5/6 x 9/20)
=-22/21 + 3/8
=-113/168
3) (-3/4) × (-1/4) × (-7/8) ÷ (-7/16)
=3/4 x 1/4 x 7/8 ÷ 7/16
=3/8
4) (+3)×(-3×-5)- 2×〔(+3)×(-5)〕 _ (+3)×(-3)
----------------------------------------- ---------------
+5 - (-6 ) + ( +3 ) -5

(3)×(3×5)+ 2×(3×5) + 3×3
= -------------------------------------------
5 + 6 + 3 -5

= 9 1/3

1) +3 1/4 - (+21/2 - 1/-2) ÷ -1/4
= +3 1/4 - (+11) ÷ -1/4
= +3 1/4 + 44
= + 47 1/4

2) (+5/7) x (-22/15) - (5/6) x (-9/20)
= (-22/21) - (-3/8)
= -113/168

3) (-3/4) x (-1/4) x (-7/8) ÷ (-7/16)
= (-3/4) x (-1/4) x (-7/8) x (16/-7)
= 3/2

4) (+3)×(-3×-5)- 2×〔(+3)×(-5)〕 _ (+3)×(-3)
----------------------------------------- ---------------
+5 - (-6 ) + ( +3 ) -5

= (+3) x (+15) - 2 x (-15) - (-9)
--------------------------------------
+5+6+3-5

= (+45) + 30 +9
--------------------
9

= 84/9
= +9 1/3

應該就這樣了!(^^)