Factorise: 9a^2-(a^2 - 4)^2
Answers
Answered by
3
Answer:
9a^2 -(a^2 -4)^2
Remember?
A^2 -B^2 =(A+B)(A-B)
Therefore,
9a^2 -(a^2 -4)^2
=(3a)^2 -(a^2 -2^2)^2
=(3a +a^2 -4)(3a -a^2 +4)
= -(a^2 +3a -4)(a^2 -3a -4)
= -(a^2 +4a -a -4)(a^2 -4a +a -4)
= -(a+4)(a-1)(a-4)(a+1)
= -(a^2 -16)(a^2 -1)
Similar questions