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(Barré) #1

= a^2 b^2 c^2  2 ab 2 bc 2 ac
Example 1. What is the square of ( 4 x 5 y)?


Solution :( 4 x 5 y)^2 ( 4 x)^2  2 u( 4 x)u( 5 y)( 5 y)^2


= 16 x^2  40 xy 25 y^2


Example 2. What is the square of ( 3 a 7 b)?


Solution :( 3 a 7 b)^2 ( 3 a)^2  2 u( 3 a)u( 7 b)( 7 b)^2


= 9 a^2  42 ab 49 b^2
Example 3. Find the square of 996 by applying the formula of square.
Solution :( 996 )^2 ( 1000  4 )^2


= ( 1000 )^2  2 u 1000 u 4 ( 4 )^2


= 1000000  8000  16
= 1000016  8000
= 992016
Example 4. What is the square of abcd?


Solution : (abcd)^2 {(ab)(cd)}^2


= (ab)^2  2 (ab)(cd)(cd)^2


= a^2  2 abb^2  2 (acadbcbd)c^2  2 cdd^2


= a^2  2 abb^2  2 ac 2 ad 2 bc 2 bdc^2  2 cdd^2


= a^2 b^2 c^2 d^2  2 ab 2 ac 2 ad 2 bc 2 bd 2 cd
Activity : Find the square with the help of the formulae :



  1. 3 xy 2 ax 2. 4 x 3 y 3. x 5 y 2 z


Example 5. Simplify :


( 5 x 7 y 3 z)^2  2 ( 7 x 7 y 3 z)( 5 x 7 y 3 z)( 7 x 7 y 3 z)^2

Solution : Let, 5 x 7 y 3 z a and 7 x 7 y 3 z b


? Given expression = a^2  2 .b.ab^2


= a^2  2 abb^2


= (ab)^2


= {( 5 x 7 y 3 z)( 7 x 7 y 3 z)}^2
[substituting the values of a and b]

=( 5 x 7 y 3 z 7 x 7 y 3 z)^2


= ( 12 x)^2


= 144 x^2

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