(i) \(\frac{2^3\times 3^4\times4}{3\times 3^2}\)
= \(\frac{2^3\times 3^4\times2^2}{3\times 3^2}\)
= \(\frac{2^5\times 3^4-1}{2^5}\) [am ÷ an = am - n]
= 33
(ii) ((52 )3 × 54) ÷ 57
= [56 × 54] ÷ 57 [(am)n = amn]
= 56 + 4 ÷ 57 [am × an = am + n]
= 510 ÷ 57
= 510 - 7 [am ÷ an = am - n]
= 53
(iii) 254 ÷ 53
= (52)4 ÷ 53
= 58 ÷ 53 [(am)n = amn]
= 58 - 3 [am ÷ an = am - n]
= 55
(iv) \(\frac{3\times7^2\times 11^8}{21\times11^3}\)
= \(\frac{3\times7^2\times 11^8}{3\times7\times11^3}\) [Since, 21 = 3 × 7]
= \(\frac{7^2\times 11^8}{7\times11^3}\)
= 72 - 1 × 118 - 3 [am ÷ an = am - n]
= 7 × 115
(v) \(\frac{3^7\times3^4}{3^3}\)
= 37 / 34 + 3 [am × an = am + n]
= \(\frac{3^7}{3^7}\)
= 37 - 7 [am ÷ an = am-n]
= 30
= 1 [ao = 1]
(vi) 20 + 30 + 40
= 1 + 1 + 1 [ao = 1]
= 3
(vii) 20 × 30 × 40
= 1 × 1 × 1 [ao = 1]
= 1
(viii) (30 + 20) × 50
= (1 + 1) × 1 [ao = 1]
= 2 × 1
= 2
(ix) \(\frac{2^8\times a^5}{4^3\times a^3}\)
= \(\frac{2^8\times a^5}{2^{2^3\times a^3}}\)
= \(\frac{2^8\times a^5}{2^6\times a^3}\) [(am)n = amn]
= 28 - 6 × a5 - 3 [am ÷ an = am - n]
= 22 × a2
(x)\(\frac{a^5}{a^3}\times a^8\)
= a5 - 3 × a8 [am ÷ an = am - n]
= a2 × a8
= a2 + 8 [am × an = am + n]
= a10
(xi) \(\frac{4^5\times a^8b^3}{4^5\times a^5b^2}\)
= 45 - 5 × a8 - 5 × b3 - 2 [am ÷ an = am - n]
= 40 × a3 × b
= a3 × b [ao = 1]
(xii) (23 × 2)2
= (23 + 1)2 [am × an = am + n]
= (24)2
= 24 × 2 [(am)n = amn]
= 28
Using laws of exponents, simplify and write the answer in exponential form:
(i) 32 × 34 × 38 (ii) 615 ÷ 610 (iii) a3 × a2 (iv) 7x×72 (v) (52) ÷ 53 (vi) 25 × 55 (vii) a4 × b4 (viii) (34)3(ix) (220 ÷ 215)×23 (x) 8t ÷ 82
Match the items given in Column I with one or more items of Column II.
Column I | Column II |
(a) A plane mirror | (i) Used as a magnifying glass. |
(b) A convex mirror | (ii) Can form image of objects spread over a large area. |
(c) A convex lens | (iii) Used by dentists to see enlarged image of teeth. |
(d) A concave mirror | (iv) The image is always inverted and magnified. |
(e) A concave lens | (v) The image is erect and of the same size as the object. |
- | (vi) The image is erect and smaller in size than the object. |