Which are the solutions of x2 = –7x – 8? StartFraction 7 Over 2 EndFraction minus StartFraction StartRoot 17 EndRoot Over 4 EndFraction comma StartFraction 7 Over 2 EndFraction + StartFraction StartRoot 17 EndRoot Over 4 EndFraction
StartFraction negative 7 Over 2 EndFraction minus StartFraction StartRoot 17 EndRoot Over 4 EndFraction comma StartFraction negative 7 Over 2 EndFraction + StartFraction StartRoot 17 EndRoot Over 4 EndFraction
StartFraction 7 minus StartRoot 17 EndRoot Over 2 EndFraction comma StartFraction 7 + StartRoot 17 EndRoot Over 2 EndFraction
StartFraction negative 7 minus StartRoot 17 EndRoot Over 2 EndFraction comma StartFraction negative 7 + StartRoot 17 EndRoot Over 2 EndFraction

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