I would solve for y on the top one and sub it into the bottom one.
y=-2x+8
(12/5, 16/5)
Prime numbers on dice: 2,3,5 (3 Possibilities)
Numbers on a dice: 1,2,3,4,5,6 (6 Possibilities)
So (3/6) or 1/2 or 50%
9/24, 18/48 these are two equivalent fractions
If both are negative then X-.Y is positive
