Find the value of m for which 5 m ÷ 5 -3 = 5 5 .

NCERT - Mathematics

Book: NCERT - Mathematics

Chapter: 12. Exponents and Powers

Subject: Maths - Class 8^th

Q. No. 5 of Exercises 12.1

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5

Find the value of m for which 5^m÷ 5^-3 = 5⁵.

Formula

a^m/aⁿ = a^(m-n)

a^m× aⁿ = a^(m+n)

aⁿ = a^m, then n = m

By using above formula in question:

5^m÷ 5^-3 = 5⁵

⇒ 5^m+3= 5⁵

⇒ m + 3 = 5

⇒ m = 2

7

Chapter Exercises

Exercises 12.1

Exercises 12.2

1

Evaluate.
(i)

(ii)

(iii)

2

Simplify and express the result in power notation with positive exponent.

(i) (-4)⁵ ÷ (-4)⁸

(ii)

(iii)

(iv) (3^-7 ÷ 3^-10) × 3^-5

(v) 2^-3 × (-7)^-3

3

Find the value of.
(i)
(ii)
(iii)
(iv)
(v)

4

Evaluate
(i)
(ii)

5

Find the value of m for which 5^m÷ 5^-3 = 5⁵.

6

Evaluate
(i)

(ii)

7

Simplify
(i)
(ii)