Yani buys a certain brand of cereal that costs $10 per box. yani changes to a super-saving brand of the same size. the equation shows the price, y, as a function of the number of boxes, x, for the new brand. y = 7x part a: how many more dollars is the price of a box of yani's original brand cereal than the price of a box of the super-saving cereal? show your work. part b: how much money does yani save each month with the change in cereal brand if he buys 5 cereal boxes each month? show your work.