ML Aggarwal CBSE Solutions Class 8 Math Second Chapter Exponents and Powers Exercise 2.1

ML Aggarwal CBSE Solutions Class 8 Math 2nd Chapter Exponents and Powers Exercise 2.1

(1) (i) (3/5)-2 = 1/(3/5)2 = (5/3)2

= 5×5/3×3 = 25/9

(ii) (-3)-3 = 1/(-3)3 = (1/-3)3 = 1x1x1/-3x-3x-3 = 1/-27

(2) (i) [(2)-1+ (4)-1+ (3)-1]-1

= [1/2 + 1/4 + 1/3]-1 = [6+3+4/12]-1 = [13/12]-1

= 1/(13/12)1 = 12/13 Ans.

(iii) [40+42-23] x3-2

= [1+16-8] x 1/32 = [17-8] x 1/32 = 9×1/9

= 1 Ans.

(4) (i) 16-2 = 1/162 = 1/(24)2 = ½8 = 2-8

(ii) 125-4 = 1/(125)4 = 1/(53)4 = 1/512 = 5-12

(5) (ii) 3007.805

= 3×1000 + 0x100 + 0x10 + 7×1 + 8/10 + 0/100 + 5/1000

= 3×10-3 + 0x10-2 + 0x10-1 + 7×1 + 8×10-1 + 0x10-2 x 5×10-3

(9) 9m ÷ 3-2 = 94

= 9m ÷ 3-2 = 94

Or, 9m ÷ 1/32 = 94

Or, 9m x 32 = 94

Or, 9m/94 = 1/9

Or, (9)m-4 = 1/9 = 9-1

Or, m-4 = -1

Therefore, m= -1+4 = 3 Ans.

(11) Let, the number should be divided by X.

Therefore, according to question –

(3/-2)-3 ÷ X = (2/3)2

Or, (3/-2)2/X = (2/3)2

Or, X = (3/-2)-3/(2/3)2

Or, X = (-2/3)3/(2/3)2 = – (2/3)3-2 = – 2/3 Ans.

(12) (-2/3)-13 x (3/-2)8 = (-2/3)-2X+1

Or, (-2/3)-13 x (-2/3)-8 = (-2/3)-2X+1

Or, (-2/3)-13-(-8) = (-2/3)-2X+1

Or, (-2/3)-13+8 = (-2/3)-2X+1

Or, (-2/3)-5 = (-2/3)-2X+1

Or, -2X+1 = -5

Or, -2X = -5-1 = -6

Or, X = 6/2 = 3 Ans.


Updated: February 18, 2021 — 5:02 pm

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