Question

evaluate the following : 998^2​

Answer 1

Solution:-

We have to Evaluate 998²

Using the identity

→ (a -b)² = a² + b² -2ab

Now, Solving

As we can write 998 = 1000 -2

here

a = 1000

b = 2

(1000-2)² = 1000² + 2² - 2×1000 × 2

= 1000000 + 4 - 4000

= 1000000 -4000 +4

= 996000 + 4

= 996004

Therefore the required answer is 996004

Additional Information!!

Some More identities!!

• (a + b)² = a² + b² +2ab

• ( a - b )² = a² + b² -2ab

• ( a² - b² ) = ( a - b ) ( a + b )

• ( a +b +c)² = (a² + b² + c²) + 2(ab + bc +ca)

• (a + b)³ = a³ + b³ + 3ab(a+b)

• (a-b)³ = a³ - b³ -3ab(a-b)

• ( a³ + b³) = (a+b) (a²-ab +b²)

• (a³ - b³) = (a -b) (a² + ab + b²)

Answer 2

$\huge\sf\underline\purple{Required answer}$

•We can solve this one by simple method using identities...

Refer the attachment..