just say the answer, Sonny substituted 5 for x in the proportion StartFraction 16 over x EndFraction = StartFraction 48 over 15 EndFraction and cross multiplied to get 240 = 240. Why is this? because the cross sums of the proportion are equal because the cross differences of the proportion are equal, because the cross products of the proportion are equal, because the cross quotients of the proportion are equal

Suppose you are an avid reader and are looking to save money on the cost of books instead of paying about $20 for each book, you decide to look into purchasing a kindle for $120 you can purchase e-books for about $5 each 1. find the slope-intercept equation for the cost of the hard copy of books using x to represent the number of books 2. find the slope-intercept equation for the cost of the kindle with cost of e-books using x to represent the number of books