Advertisements
Advertisements
Question
Using algebraic identity, find the coefficients of x2, x and constant term without actual expansion
(2x + 3)(2x – 5)(2x – 6)
Advertisements
Solution
(2x + 3)(2x – 5)(2x – 6)
∴ Co-efficient of x2 = 4 (a + b + c)
= 4(3 + (– 5) + (– 6))
= 4 × (– 8) = – 32
Co-efficient of x = 2 (ab + bc + ca)
= 2[3 × (– 5) + (– 5)(– 6) + (– 6)(3)]
= 2[–15 + 30 – 18] = 2 × (– 3) = – 6
Constant term = abc
= 3 × (– 5) × (– 6)
= 90
APPEARS IN
RELATED QUESTIONS
Simplify the following using the formula: (a − b)(a + b) = a2 − b2: (467)2 − (33)2
Simplify the following using the formula: (a − b)(a + b) = a2 − b2: 1.8 × 2.2
Multiply the following:
(2x – 2y – 3), (x + y + 5)
Simplify:
(3x + 2y)2 – (3x – 2y)2
Expand the following, using suitable identities.
`(4/5p + 5/3q)^2`
Expand the following, using suitable identities.
`((2x)/3 - 2/3)((2x)/3 + (2a)/3)`
Expand the following, using suitable identities.
(0.9p – 0.5q)2
Using suitable identities, evaluate the following.
(98)2
Carry out the following division:
51x3y2z ÷ 17xyz
Match the expressions of column I with that of column II:
| Column I | Column II |
| (1) (21x + 13y)2 | (a) 441x2 – 169y2 |
| (2) (21x – 13y)2 | (b) 441x2 + 169y2 + 546xy |
| (3) (21x – 13y)(21x + 13y) | (c) 441x2 + 169y2 – 546xy |
| (d) 441x2 – 169y2 + 546xy |
