Question

expand ( x + 2y -3z)2 using identities

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Answer 1

Answer:

Step-by-step explanation:

We need to expand (x+2y+3z)^  2

 We know appropriate identity (x+y+z)  ^2  =x  ^2

+ y  ^2  + z  ^2  +2xy+2yz+2xz

Therefore, the value of (x+2y+3z)  ^2   is

=x  ^2  +(2y)  ^2  +(3z)  ^2

+2(x)(2y)+2(2y)(3z)+2(x)(3z)

=x^2  +4y ^

2  +9z^  2  +4xy+12yz+6xz

Answer 2

Answer:

 x2+4y2+9z2+4xy+6xz+12yz

Comparing the given expression with (x+y+z)2

We have x = x , y = 2y and z = 3z

Hence using the identity (x+y+z)2 = x2+y2+z2+2xy+2yz+2xz

We have (x+2y+3z)2 =

⇒

x2+(2y)2+(3z)2+2(x)(2y)+2(x)(3z)+2(2y)(3z)

⇒x2+4y2+9z2+4xy+6xz+12yz