Question

Factorise : 3 - a (4 + 7a)

Answer 1

3 - a (4 + 7a) 
= 3 - 4a - 7a2
= 3 - 7a + 3a - 7a2
= 1( 3 - 7a ) + a( 3 - 7a )
= ( 3 - 7a )( a + 1 )