What needs to be done to the two constraints in order to convert the problem to a standard form?

MAX:	8 X1 + 4 X2
Subject to:	5 X1 + 5 X2 20
	6 X1 + 2 X2 18
	X1, X2 0

	a.	a slack variable needs to be added to each constraint to convert them to equalities.
	b.	they need to be combined to a single constraint.
	c.	nothing.
	d.	they need to be subtracted side-by-side