Question

Q 2. Solve the following according to the given instructions Evaluate using suitable Identities 1.(2a+7) (2a-7)​

Answer 1

Answer:

(2a−7)(2a−7)=(2a−7)

2

using identity (a−b)

2

=a

2

−2ab+b

2

(2a−7)

2

=(2a)

2

−2×2a×7+7

2

(2a−7)

2

=4a

2

−28a+49

Answer 2

Given:

The equation is (2 a+ 7) (2 a-7).

To find:

We have to evaluate the equation using a suitable identity.

Solution:

Since the quadratic equation (2 a + 7) (2 a - 7) is in the form of algebraic identity (x + y) (x- y).

Therefore, we will use the following algebraic identity.

(x + y) (x-y) = x² - y²

(2 a + 7) (2 a - 7) = ( 2 a)² - (7)²

= 4 a² - 49

Using suitable identity, the equation (2 a + 7) (2 a - 7) is equal to 4 a² - 49.