Chapter 12 Exponents and Powers

Chapter 12 Exponents and Powers

Exercise 12.1

Ex 12.1 Class 8 Maths

Question 1.
Evaluate:
(i) 3^-2
(ii) (-4)^-2
(iii) ( )^-5

Solution:

Ex 12.1 Class 8 Maths 

Question 2.
Simplify and express the result in power notation with a positive exponent.

Solution:

Ex 12.1 Class 8 Maths 

Question 3.
Find the value of

Solution:

Ex 12.1 Class 8 Maths 

Question 4.

Solution:

Ex 12.1 Class 8 Maths 

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

Solution:
5^m ÷ 5^-3 = 5⁵
⇒ 5^m-(-3) = 5⁵ [∵ a^m ÷ aⁿ = a^m-n]
⇒ 5^m+3 = 5⁵
Comparing the powers of equal bases, we have
m + 3 = 5
m = 5 – 3 = 2, i.e., m = 2

 

 

 

 

Ex 12.1 Class 8 Maths 

Question 6.
Evaluate:

Solution:

Ex 12.1 Class 8 Maths 

Question 7.
Simplify:

Solution: