NCERT Solutions Class-7 Maths chapter-13 Exponents and Powers Exercise-13.2 is prepared by academic team of pw all the questions of NCERT text book are solved step by step with proper and detail solutions explaining each and every questions . For More and additional questions of CBSE class 7 maths you can go to class 7 maths sections. NCERT class 7 Maths Solutions is the best way to enhanced your mathematics skill. And pw practice worksheet & question bank will help you a lot .
Question 1:
Using laws of exponents simplify and write the answer in exponential form:
(i) 3 2 × 3 4 × 3 8
(ii)
(iii) a 3 × a 2
(iv) 7 x × 7 2
(v)
(vi )2 5 × 5 2
(vii) a 4 × b 4
(viii)(3 4 ) 3
(ix)
(x)
Answer:
(i) We have,
3 2 × 3 4 × 3 8
We know that,
(a m × a n = a m + n )
Thus,
3 2 × 3 4 × 3 8
= (3) 2 + 4 + 8
= 3 14
(ii) We have,
6 15 6 10
We know that,
(a m a n = a m - n )
Thus,
6 15 6 10
= (6) 15 - 10
= 6 5
(iii) We have,
a 3 × a 2
We know that,
(a m × a n = a m + n )
Therefore,
a 3 × a 2
= (a) 3 + 2
= a 5
(iv) We have,
7 x × 7 2
We know that,
(a m × a n = a m + n )
Thus,
7 x × 7 2
= (7) x + 2
(v) We have,
(5 2 ) 3 5 3
Using identity:
(a m ) n = a m × n
= 5 2 × 3 5 3
= 5 6 5 3
We know that,
(a m a n = a m - n )
Thus,
5 6 5 3
= (5) 6 - 3
= 5 3
(vi) We have,
2 5 × 5 5
We know that,
[a m ×b m = (a × b) m ]
Thus,
2 5 × 5 5
= (2 × 5) 5 + 5
= 10 5
(vii) We have,
a 4 × b 4
We know that,
[a m × b m = (a × b) m]
Thus,
a 4 × b 4
= (a × b) 4
(viii) We have,
(3 4 ) 3
We know that,
(a m )n = a mn )
Thus,
(3 4 ) 3
= (3 4 ) 3
= 3 12
(ix) We have,
(2 20 2 15 ) × 2 3
We know that,
(a m a n = a m - n )
Thus,
(2 20 - 15 ) × 2 3
= (2) 5 × 2 3
We know that,
(a m × a n = a m + n )
Thus,
(2) 5 × 2 3
=(2 5 + 3 )
= 2 8
(x) We have,
(8 t 8 2 )
We know that,
(a m a n = a m - n )
Thus,
(8 t 8 2 )
= (8 t – 2 )
NCERT CLASS 7 MATHEMATICS SOLUTIONS