Question

Expand (x+2y−z)2 using identities .

Answer 1

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We need to expand (x+2y+4z)

2

We know appropriate identity (x+y+z)

2

=x

2

+y

2

+z

2

+2xy+2yz+2xz

Therefore, the value of (x+2y+4z)

2

is

=x

2

+(2y)

2

+(4z)

2

+2(x)(2y)+2(2y)(4z)+2(x)(4z)

=x

2

+4y

2

+16z

2

+4xy+16yz+8xz