Question

factorise by regrouping 1+a²b²+a²+b²​

Answer 1

Answer:

(a²-1)(b²-1)

Step-by-step explanation:

a²b²-a²-b²+1

=>a²(b²-1)-1(b²-1)                [taking a²common from first two terms and -1                            

                                            common from last two terms]

=>(b²-1)(a²-1)                          [taking (b²-1) common from both the terms]