Question

3. Using the identity for difference of two squares, find the values of:


(203)2 – (197)2
​

Answer 1

Consider 203 = a & 197 = b

therefore,(203)^2 - (197)^2 = a^2 - b^2

We know,a^2 - b2 = (a+b)×(a-b)

=> (203)^2 -(197)^2 = (203 + 197) × (203 - 197)

= 400 × 6 = 2400 ans.

Answer 2

Given:

203² - 197²

What to find?

The difference using an identity.

How to find?

We will use the identity a² - b² = (a + b) (a - b) where a is 203 and b is 197.

Solution:

Using the identity,

a² - b² = (a + b) (a - b)

Substitute the values,

⇒ (203 + 197) (203 - 197)

Solve the brackets,

⇒ 400 × 6

Mutliply the numbers,

⇒ 2400

∴ So, the answer is 2400.