Question

W hich of the following should be added to make x 4 + 64 a perfect square (A) 4x2 (B) 16x2 (C) 8x2 (D) -8x2

Answer 1

Answer:

(B)

Step-by-step explanation:

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

we have a^2 term given as x^4

so a is x^2

we have b^2 term given as 64 so b is sqrt of 64 which is 8

so we write it in the form of (a + b) ^2

(x^2 + 8)^2 and on expansion we get

=x^4 + 16x^2 + 64

and hence 16x^2 should be added.

Answer 2

Option b. 16x2 are the correct answer