Question

Factorise :
9a²-(a²-4)²​

Answer 1

Answer:

9a²-(a²-4)²​=-(a+4)(a-1)(a-4)(a+1)

Step-by-step explanation:

• 9a²-(a²-4)²​=                 use of formula:  a²-b²=(a+b)(a-b)

• (3a+a²-4)(3a-a²+4)=
• -(a²+3a-4)(a²-3a-4)=
• -(a+4)(a-1)(a-4)(a+1)

Answer 2

Answer:

Therefore a=1 and 4..

Step-by-step explanation:

9a²-(a⁴+16-8a²)

9a²-a⁴-16+8a²

17a²-a⁴-16

Or it can be written as

a⁴-17a²+16

a⁴-16a²-a²+16

a²(a²-16)-1(a²-16)

a²-1(a²-16)

Therefore a=1 and 4..

hope you understand