=> ab(a+b) + bc (b+c) + ca(c+a) + 2abc
= >a\(^2\)b + ab\(^2\) + b\(^2\)c + bc\(^2\) + ac\(^2\) + a\(^2\)c + 2abc
=> a(ab + b\(^2\) + ac + 2bc) + bc(b + c)
=> a[a(b + c) + (b + c)2 ] + bc(b + c)
=> a(a + b + c)(b + c) + bc(b + c)
=> (b + c) (a\(^2\)+ ab + ac + bc)
=> (b + c)(a + b)(b + c)