A mirror With a parabolic cross-section is used to collect sunlight on a pipe located at the focus of the mirror. The pipe is located 3 inches from the vertex of the mirror. Write in equation of the parabola that models the cross section of the mirror assume The parabola opens upward

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?