The product of the slopes of two non-vertical perpendicular lines is always -1. It is NOT possible for two perpendicular lines to both have a positive slope because the product of two positives is positive. So for the product of the slopes to be -1, one of the slopes must be positive and the other negative. True or False

The customer price index(cpi), which measures the cost of a typical package of customer goods,was 208.8 in 2011 and 244.1 in 2016.let x=11 corresponding to the year 2011 an estimate to cpi into 2013 and 2014. assume that the data can be modeled by a straight line and the trend to continue idenfinitely.use data points to find such a line and then estimate the requested quantities

Can someone show me step by step how to do this?

How many quarts of a 50% solution of acid must be added to 20 quarts of a 20% solution of acid in order to get a 40% solution of acid?