exam Maths Puzzle Numerical Ability

i am trying to the

Read Solution (Total 0)

exam Other Question

ok i do not understand how to do this......X/X+2+ 3/X-2=7/X expressions/53089 (2006-09-21 00:55:06): I need to justify each of these step, please help me with this.
5(n+4)+9n= (5n+20)+9n
=5n+(20+9n)
=5n+(9n+20)
=(5n+9n)+20
=(5+9)n+20
=14n+20