Question

expand (3x-y+z)²
class 9th ques.​

Answer 1

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We can expand it with two methods,

First Method →

Directly by using algebraic identities( a+b+c)²

Second Method →

By stepbby step explanation

$\large{\boxed{\underline{\overline{\bf{\blue{ Solving\: by\: using\: first\: method→}}}}}}$

(a+ b + c ) ² = a² + b² + c² + 2ab + 2bc + 2ac

[ In given question, a = 3x, b = -y, c = z]

Substituting value in identities -

(3x-y+z)² = (3x)² + (-y)² + z² + (2×3x ×-y) +(2× -y×z )+(2×3x × z )

==> 9x² + y² + z² -6xy -2yz + 6xz

$\large{\boxed{\underline{\overline{\bf{\blue{ Solving\: by\: using\: second\: method→}}}}}}$

(3x-y+z)² = (3x-y+z) × (3x-y+z)

=> 3x ( 3x-y+z) -y (3x-y+z) +z ( 3x-y+z)

=> 9x² - 3xy +3xz -3xy + y² -yz + 3xz - zy + z²

=> 9x² - 6xy + 6 xz +y² -2yz + z²

=> 9x² + y² + z² -6xy + 6xz - 2yz

Answer 2

Answer: UR REQUIRED ANSWER ;-

(a+b+c)² = a² + b ² + c ² +2ab +2bc +2ac

in given question  ;-

a = 3x , b = -y and c = z

now , substituting value in identities .

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

= 9 x² + y² + z² -6xy -2yz + 6xz .

Step-by-step explanation: hope this will help u mate ,, need fedback plz

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