Let x represent the number of quarts of Tuscan sauce and
y represent the number of quarts of marinara sauce Tiffany makes.
A quart of Tuscan sauce requires 6 tomatoes and 1 cup of oil
x quarts requires 6x tomatoes and 1x cups of oil
A quart of her marinara sauce requires 5 tomatoes and 1.25 cups of oil
y quarts requires 5y tomatoes and 1.25 y cups of oil
She has 45 tomatoes and 10 cups of oil on hand.
So the constraints are


x>=0 and y>=0