Question

Evaluate using suitable identity:
h). 139² - 138²​

Answer 1

277

Explanation:

Algebraic Identity: a²-b²=(a-b)(a+b)

Hence,

139²-138²=(139-138)(139+138)

=1×277

=277

Answer 2

Explanation:

★ Solution :-

`\sf \longmapsto 139^2 - 138^2`

`\sf \longmapsto a^2 - b^2 = (a + b)(a - b)`

Here,

• a = 139
• b = 138

`\sf \longmapsto 139^2 - 138^2 = (139 + 138)(139 - 138)`

`\sf \longmapsto (239 + 138)(239 - 138)`

`\sf \longmapsto (377)(1)`

`\sf \longmapsto 377`

Hence solved !!