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Home >> Standard Identities & their applications >> (a + b)2 = a2 + b2 + 2ab >> A + B Whole Square
Before you understand A + B Whole Square : (a + b)2 = a2 + b2 + 2ab, you are advised to read:
How to Multiply Variables ?
How to Multiply Polynomials ?
What is Exponential Form ?
How this identity of (a + b)2 = a2 + b2 + 2ab is obtained:
Taking LHS of the identity:
(a + b)2
This can also be written as:
= (a + b) (a + b)
Multiply as we do multiplication of two binomials and we get:
= a(a + b) + b(a + b)
= a2 + ab + ab + b2
Add like terms and we get:
= a2 + 2ab + b2
Rearrange the terms and we get:
= a2 + b2 + 2ab
Hence, in this way we obtain the identity i.e. (a + b)2 = a2 + b2 + 2ab
Following are few applications of identity first:
Example 1: Solve (4p + 5q)2
Solution: This proceeds as:
Given polynomial (4p + 5q)2 represents identity first i.e. (a + b)2
Where a = 4p and b = 5q
Now apply values of a and b on the identity i.e. (a + b)2 = a2 + b2 + 2ab and we get:
(4p + 5q)2 = (4p)2 + (5q)2 + 2(4p)(5q)
Expand the exponential forms and we get:
= 16p2 + 25q2 + 2(4p)(5q)
Solve multiplication process and we get:
= 16p2 + 25q2 + 40pq
Hence, (4p + 5q)2 = 16p2 + 25q2 + 40pq
Example 2: Solve (8x + 4y)2
Solution: This proceeds as:
Given polynomial (8x + 4y)2 represents identity first i.e. (a + b)2
Where a = 8x and b = 4y
Now apply values of a and b on the identity i.e. (a + b)2 = a2 + b2 + 2ab and we get:
(8x + 4y)2 = (8x)2 + (4y)2 + 2(8x)(4y)
Expand the exponential forms and we get:
= 64x2 + 16y2 + 2(8x)(4y)
Solve multiplication process and we get:
= 64x2 + 16y2 + 64xy
Hence, (8x + 4y)2 = 64x2 + 16y2 + 64xy
Study More Solved Questions / Examples
Solve the following equations by A + B Whole Square
A) (22x + 27y)2
B) (14x + 7y)2
C) (15x + 9y)2
D) (18x + 4y)2 |
Solve the following equations by A + B Whole Square
E) (9x + 3y)2
F) (13x + 7y)2
G) (16x + 7y)2 |
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