Here's a graphical solution for the second one :
https://www.desmos.com/calculator/fnueaahoif
If we let x be the number of pies and y be the number of batches of brownies.....we can graph the inequality
8x + 12y ≤ 112
Lookng at the graph....we can forget the points inside the shaded area....these combinations will not yield enough desserts
Note that the red dot - representing 3 pies and 8 batches of brownies - is closer to the boundary of the inequality than the points (2, 9) and (5,7)
So
(3, 8) yields = 120 desserts
(2, 9) yields = 124 desserts
(5, 7) yields = 124 desserts
So.....we want to choose 3 pies and 8 batches of brownies
Thanks to EP for spotting my earlier error !!!