Question

4. Ifa=2,b=-2, find the value of:
(i) a + b (ii) a² + ab + b?​

Answer 1

Answer:

Step-by-step explanation:

We know that

(a - b)² = a² + b² - 2ab

Here ab = 4

a² + b² = 41

By substituting the values

⇒ (a - b)² = (41) - 2(4)

⇒ (a - b)² = 41 - 8

⇒ (a - b)² = 33

⇒ a - b = √33

Verification :-

(a - b)²= a² + b² - 2ab

⇒ (√33)² = (41) - 2(4)

⇒ 33 = 41 - 8

⇒ 33 = 33

Therefore a - b = √33

Identity used :-

• (a - b)² = a² + b² - 2ab

Extra Information :-

Some Important Identities :-

• (x + y)² = x² + y² + 2xy

• (x - y)² = x² + y² - 2xy

• (x + y)(x - y) = x² - y²

• (x + a)(x + b) = x² + (a + b)x + ab

• (x + y + z)² = x² + y² + z² + 2xy + 2yz + 2xz

Answer 2

Answer:

(i)0

(ii)-2

Step-by-step explanation:

(i)a+b=2+(-2)=2-2=0

(ii)a²+ab+b=2²+2(-2)+(-2)=4+(-4)+(-2)

=4-4-2=-2

Hope it helps!