Question

Expand using suitable identities: (2.5y + z) (2.5y - z)​

Answer 1

Answer:

6.25y^2 - z^2

Step-by-step explanation:

we will use identity 3

(2.5y + z) (2.5y - z)​

= (2.5y) ^2 -( z)^2

=(6.25y^2 ) - (z^2)

= 6.25y^2 - z^2

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Answer 2

Answer:

Expansion of $( 2.5 y + z ) ( 2.5y -z )$ is $6.25 y^{2} - z^{2}$ .

Step-by-step explanation:

To expand : $( 2.5 y + z ) ( 2.5y -z )$ .

Solution :

• Algebraic identities are algebraic equations which are always true for every value of variable in them .
• In the given expression , we can see that it is of the form of identity , $a^{2} + b^{2} = (a-b )(a + b )$ .
• Here, $a = 2.5y$  and  $b =z$ .
• Applying above identity to $( 2.5 y + z ) ( 2.5y -z )$ we get ,  

       $( 2.5 y + z ) ( 2.5y -z )\\\\= (2.5y )^{2} -(z)^{2} \\\\=6.25y^{2} - z^{2}$