问题1.评估:
解决方案:
(i) 3–2
3-2 = (Property used: a-n = )
(ii) (– 4)– 2
(-4)-2 = (Property used: a-n = )
(iii) () -5
()-5 = (2)5 = 32 (Property used: )
问题2:用幂指数简化并以幂符号表示结果。
解决方案:
(i) (-4)5 ÷ (-4)8
= (-4)5-8 = (-4) -3 (Property used: am ÷ an= am-n)
=
=
(ii)
= (Property used: (am)n = am×n)
=
=
(iii) (-3)4 × ()4
= ((3)4 × (Property used: (a/b)n = an/ bn & (-a)n = an if a is positive number and n is even)
= 54
(iv) (3-7 ÷ 3-10) × 3-5
= 3 (-7-(-10)) × 3-5 (Property used: am ÷ an= am-n)
= 3 (-7+10) × 3-5
= 33 × 3-5
= 3 (3+(-5)) (Property used: am × an = a m + n)
= 3-2 (Property used: a-m =)
=
=
(v) 2-3 × (-7)-3
= (2 × (-7))-3 (Property used: am × bm = (a×b)m)
= (-14)-3 (Property used: a-m =)
=
=
问题3.找到的价值
解决方案:
(i) (30 + 4-1) × 22
= (1 + ()) × 4 (a0 = 1 a ≠ 0)
= () × 4
= 5
(ii) (2-1 × 4-1) ÷ 2-2
= (2 × 4)-1 ÷ (Property used: am × bm = (a×b)m)
= (8)-1 ÷
= () ÷
=() × 4
= ()
(iii) (1/2)-2 + (1/3)-2 + (1/4)-2
= 22 + 32 + 42 (Property used: =am)
= 4 + 9 + 16
= 29
(iv) (3-1 + 4-1 + 5-1)0
= ()0 (a0 = 1 (a ≠ 0)
= 0
(v) {()-2}2
= () -2×2 (Property used: (am)n = am×n)
= ()-4 = ()4 (Property used: (b/a)-n = an/bn)
=
=
问题4:评估
解决方案:
(i) (8-1 × 53) / 2-4
= ( × 125) / (2-4) (Property used: (b/a)-n = an/bn)
= () × 125 × 24
= 250
(ii) (5-1 × 2-1) × 6-1
= (5 × 2)-1 × 6-1 (Property used: am × bm = (a×b)m)
= 10-1 × 6-1
= (10 × 6)-1 (Property used: am × bm = (a×b)m)
= 60-1
=
问题5.找到5 m ÷5 – 3 = 5 5的m的值
解决方案:
5m-(– 3) = 55 (Property used: am ÷ an= am-n)
5m+3 = 55
m+3 = 5
m = 5-3
m = 2
问题6:评估
解决方案:
(i) {()-1 – ()-1}-1
= (31 – 41) -1 (Property used: (1/a)-m = am)
= (-1)-1
= (1/(-1))1
= (-1)
(ii) ()-7 × ()-4
= ()7 × ()-4 (Property used: (b/a)-n = (a/b)n)
= () 7+ (-4) (Property used: am × an = a m + n)
= ()3 = 83/53
=
问题7.简化
解决方案:
(i) (t ≠ 0)
= (Property used: am ÷ an= am-n ) (25 = 52)
=
=
=
(ii)
=
= (Property used: (a×b)m = am × bm)
= (3-5-(-5) × 2-5-(-5) × 5 (-5)+3+7) (Property used: am ÷ an= am-n )
= (30 × 20 × 55) (a0 = 1 (a ≠ 0)
= 55