Expand using suitable identities: (2x + 9) (2x - 7)

Solution:

Given, (2x + 9) (2x - 7)

Using standard identity: (x + a) (x + b) = x² + (a + b)x + ab

Here, a = 9 and b = -7

(2x + 9) (2x - 7) = (2x)² + [(9 - 7)(2x)] - 63

= 4x² + 4x - 63

✦ Try This: Expand using suitable identities: (4a - 3)(4a + 5)

Given, (4a - 3)(4a + 5)

Using standard identity: (x + a) (x + b) = x² + (a + b)x + ab

(4a - 3)(4a + 5) = (4a)² + (-3 + 5)4a + (-3)(5)

= 16a² + 8a - 15

☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 9

NCERT Exemplar Class 8 Maths Chapter 7 Problem 85(vii)

Expand using suitable identities: (2x + 9) (2x - 7)

Summary:

Expanding (2x + 9) (2x - 7) we get, 4x² + 4x - 63

☛ Related Questions:

• Expand using suitable identities: [(4x/5) + (y/4)] [(4x/5) + (3y/4)]
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• Expand using suitable identities: (2x - 5y) (2x - 5y)