有向數 (8題) F.1 >o

我唔係好識計,請問可唔可以幫吓我
----- 負數乘負數 等於 正數

負負得正
負正得負

1. -5(12-2)+(2-36)

= (-5)x12 + (-5)x(-2)+2-36
= -60 + 10 + 2 - 36
=-60 + 12 -36
= -60 -24
= - 84

2. (-6)(+7)-(-3)(- 4)+(-25)
=-42 -12 - 25
= -54 -25
= - 79

3. 3(- 4)(3)-5(3-8)
= 3(-12) - 5(-5)
= -36 +25
= - 11

4. [6/10+(- 6)]x[36+7x(- 4)/3
= [6/10 -6 ] x [36 - 28/3]
= [3/5 - 6 ] x [36 - 28/3]
= [(3-6x5)/5 ] x [36x3/3 - 28 /3]
= [(-27)/5] x [108/3 - 28/3]
= [-27/5] x [80/3]
= (-27x80)/(5x3)
=(-27/3)x(80/5)
= (-9)x16
=-144

5. [(- 4)-(-1)]/(-5x2+15)x[6-3x(-5)]

=[(-4)+1]/(-10+15)x[6+15]
= (-3)/5x21
=-63/5

6. 0/1-(2/3-1/2)/(-1/5)
= 0 + [(2x2/(3x2) - 1x2/(2x3)]/(1/5)
= (4/6-2/6)/(1/5)
= (2/6)/(1/5)
= 2x1/(6x5)
= 2/30
= 1/15


7. -1/7[-28-(-56)]

= -[-4-(-8)]
= -[-4+8]
= -[4]
=-4

8. [-1/3+1/2-(+1/4)-(-1/5)]X [(1/2)-(-1/4)]
= [-2/6+3/6 -1/4+1/5]x[1/2+1/4]
=[1/6-1/4+1/5]x[2/4+1/4]
= [1/6-1/4+1/5]x[3/4]
= [4/6-1+4/5]x3
=[12/6-3+12/5]
=2-3+12/5
=-1+1+7/5
=7/5

1. -5(12-2)+(2-36)
=-5(10)+(-34)
=-50-34
=-84

2. (-6)(+7)-(-3)(- 4)+(-25)
=(-42)-(12)+(-25)
=-42-12-25
=-79

3. 3(- 4)(3)-5(3-8)
=(-36)-5(-5)
=-36+25
=-11

4. [6/10+(- 6)]x[36+7x(- 4)/3
=(-27/5)x(36-28)/3
=(-27/5)x(8)/3
=-72/5

5. [(- 4)-(-1)]/(-5x2+15)x[6-3x(-5)]
=(- 4+1)/(-10+15)x[6-(-15)]
=(-3)/(5)(21)
=(-3)/(105)
=-1/35

6. [0/1-(2/3-1/2)]/(-1/5)
=[0-(1/6)]/(-1/5)
=(-1/6)/(-1/5)
=5/6

7. -1/7[-28-(-56)]
=-1/7(-28+56)
=-1/7(28)
=-4

8. [-1/3+1/2-(+1/4)-(-1/5)]X[(1/2)-(-1/4)]
=(-1/3+1/2-1/4+1/5)X(1/2+1/4)
=(7/60)X(1/8)
=7/480