Unsure of what you're asking.
If you have an algebraic expression in front of you and see a number there, you could label it as "known" or "a known quantity." Another word that comes to mind is "constant."
15
5x-2y=9......(1)
6x+ky=4......(2)
slope of eqn i= -5/-2
=5/2
slope of eqn ii = -6/k
since the line are perpendicular
5/2 * -6/k = -1
-30= -2k
k=15
Rolling a sum of seven with a pair of dice...any of the six numbers can be first so that probability is:
(6/6) or 1 :P
Now to roll a sum of seven only one unique number can follow the first so the probability of getting that unique number so that you have a sum of seven is:
(1/6)
This is a compound event because two thing must happen and you multiply their respective probabilities to get the probability of the compound even..
(6/6)(1/6)=6/36=1/6
