Question

(y^2-2y)-2 ^2 solve using identity.Algebra class 8

Answer 1

Answer:=-3y^4+4

Step-by-step explanation:

(y^2-2y)-2 ^2

As (a-b)^2=a^2+b^2-2ab

And in the question,

(y^2-2y) is "a" and 2 is "b"

So,

[(y^2-2y)-2]^2=(y^2-2y)^2+(2)^2-2[(y^2-2y)-2]

(y^2-2y)^2=(y^2)^2+(2y)^2-2(y^2)(2)

= y^4+4y^2-4y^2

=y^4

So,

[(y^2-2y)-2]^2=(y^2-2y)^2+(2)^2-2[(y^2-2y)(2)]

=y^4+4-2(y^4)(2)

=y^4+4-4y^4

=-3y^4+4