What do they mean by let statements and checks? ?

The vet charges $45 for an office visit and $10 for each vaccination your dog needs. write an eaquation

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

An equation in slope-intersept form the lines that passes thought (-8,1) and is perpindicular to the y=2x-17.