SAHMom S2 Mathematics Question post on Fri, 19/05/2017 1:23pm Please factorise the expression completely: (1-a2) (1-b2) + 4ab I can’t solve this… Pls help and thank you.
jieheng Post on Fri, 19/05/2017 7:40pm (1 – a²)(1 – b²) + 4ab = 1 – a² – b² + a²b² + 4ab = 1 + 2ab + a²b² – (a² – 2ab + b²) = (1 + ab)² – (a – b)² =(1 + ab + a – b) (1 + ab – a + b)
