Using identities, evaluate.
(i) 
(ii) 
(iii) 
(iv) 
(v) 
(vi) 
(vii)
(viii)
(ix) 
(i) We can write 70 as 70 + 1
Using Identity (a + b) 2 = a2 + 2ab + b2 for finding the value of 
In the given expression a = 
On substituting these values in the above identity, we get
⇒ 
(ii) We can write 100 as 100 - 1
Using Identity (a - b) 2 = a2 - 2ab + b2 for finding the value of 
In the given expression a = 
On substituting these values in the above identity, we get
⇒ 
(iii) We can write 102 as 100 + 2
Using Identity (a + b) 2 = a2 + 2ab + b2 for finding the value of 
In the given expression a = 
On substituting these values in the above identity, we get
⇒ 
(iv) We can write 998 as 1000 - 2
Using Identity (a - b) 2 = a2 - 2ab + b2 for finding the value of 
In the given expression a = 
On substituting these values in the above identity, we get
⇒ 
(v) We can write 5.2 as 5 + 0.2
Using Identity (a + b) 2 = a2 + 2ab + b2 for finding the value of 
In the given expression a = 
On substituting these values in the above identity, we get
⇒ 
(vi) 297× 303
We can write 297 as 300 – 3 and 303 as 300 + 3
Using Identity 
In the given expression 
On substituting these values in the above identity, we get
=
(vii) 78 × 82
We can write 78 as 80 – 2 and 82 as 80 + 2
Using Identity 
In the given expression 
On substituting these values in the above identity, we get
=
(viii) We can write 8.9 as 8 + 0.9
Using Identity (a + b) 2 = a2 + 2ab + b2 for finding the value of 
In the given expression a = 
On substituting these values in the above identity, we get
⇒ 
(ix) 1.05 × 9.5 = 1.05 × 0.95 × 10
We can write 1.05 as 1 + 0.05 and 0.95 × 10 as (1 – 0.05) × 10
Using Identity 
