Expand using suitable identities: (x + 3)(x + 7)

Solution:

Given, (x + 3) (x + 7)

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

Here, a = 3 and b = 7

(x + 3) (x + 7) = x² + (3 + 7)x + (3)(7)

= x² + 10x + 21

✦ Try This: Expand using suitable identities: (p - 5) (p - 4)

Given, (p - 5) (p - 4)

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

(p - 5) (p - 4) = p² + (-5-4)p + 20

= p² - 9p + 20

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

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

Expand using suitable identities: (x + 3)(x + 7)

Summary:

Expanding (x + 3) (x + 7) we get, x² + 10x + 21

☛ Related Questions:

• Expand using suitable identities: (2x + 9) (2x - 7)
• Expand using suitable identities: [(4x/5) + (y/4)] [(4x/5) + (3y/4)]
• Expand using suitable identities: [(2x/3) - (2/3)] [(2x/3) + (2a/3)]