Question

( x^2 – 9 )( x^2 – 9 )
which identity is going to be used?
also solve the question​

Answer 1

(x^2-9)(x^2-9)

formula is (a-b)^2=a^2-2ab+b^2

(x^2-9)(x^2-9)= (x^2)2 -2(x^2)(9)+(9)^2

=x^4-18x^2+81