Answer:
$5.85 = cost for fluffy slime
4r + 2(5.85) = 53.5
Explanation:
Let r = cost of regular
f = cost of fluffy
(1) 3r + 9f = 84 (2) 4r + 2f = 53.5
4 x (1) 12r + 36f = 336
-3 x (2) -12r - 6f = -160.5
30f = 175.5
f = $5.85 = cost for fluffy slime
4r + 2(5.85) = 53.5
4r + 11.7 = 53.5
4r = 41.8
r = $10.45 = cost for regular