constraint question..

A gardener requires fertiliser to have a minimum of 80 units of nitrogen, 15 units of
potassium and 10 units of iron. Two fertiliser mixes are available.
Brand X contains 20, 2 and 1 units of the minerals while
Brand Y contains 4, 1, 2 units of the minerals respectively.
Brand X costs £18 per kg while brand Y costs £6 per kg.

Write down the inequality constraints and the equation of the cost function.


thanks for anyone help+__+