A biologist studied the populations of white-sided jackrabbits and black-tailed Jackrabbits over a 5-year period. He modeled the populations, in thousands, with the following polynomials where x is time, in years.

White-sided jackrabbits: 6.5x^2 – 8.7x + 5.9
Black-sided jackrabbits: 6.5x² + 9.2x + 1.2

What polynomial models the total number of white-sided and black-sided jackrabbits?

Farmers know that driving heavy equipment on wet soil compresses the soil and injures future crops. here are data on the "penetrability" of the same type of soil at two levels of compression. penetrability is a measure of how much resistance plant roots will meet when they try to grow through the soil. compressed soil 2.85 2.66 3 2.82 2.76 2.81 2.78 3.08 2.94 2.86 3.08 2.82 2.78 2.98 3.00 2.78 2.96 2.90 3.18 3.16 intermediate soil 3.17 3.37 3.1 3.40 3.38 3.14 3.18 3.26 2.96 3.02 3.54 3.36 3.18 3.12 3.86 2.92 3.46 3.44 3.62 4.26 use the data, omitting the high outlier, to give a 95% confidence interval for the decrease in penetrability of compressed soil relative to intermediate soil. compute degrees of freedom using the conservative method. interval: to