Tamil Nadu Board of Secondary EducationSSLC (English Medium) Class 9th
Advertisement Remove all ads

# Using algebraic identity, find the coefficients of x2, x and constant term without actual expansion (x + 5)(x + 6)(x + 7) - Mathematics

Sum

Using algebraic identity, find the coefficients of x2, x and constant term without actual expansion

(x + 5)(x + 6)(x + 7)

Advertisement Remove all ads

#### Solution

(x + 5)(x + 6)(x + 7)

(x + a)(x + b)(x + c) ≡ x3 + (a + b + c)x2 + (ab + bc + ca)x + abc

Co-efficient of x2 = a + b + c = 5 + 6 + 7 = 18

Co-efficient of x2 = ab + bc + ca

= (5 × 6) + (6 × 7) + (7 × 5)

= 30 + 42 + 35

= 107

Constant term = abc = 5 × 6 × 7

Co-efficient of constant term = 210

Is there an error in this question or solution?
Advertisement Remove all ads

#### APPEARS IN

Samacheer Kalvi Mathematics Class 9th Tamil Nadu State Board
Chapter 3 Algebra
Exercise 3.4 | Q 2. (i) | Page 101
Advertisement Remove all ads
Advertisement Remove all ads
Share
Notifications

View all notifications

Forgot password?