1.Solve the system using elimination. 4x + 4y = 12
7x - 4y = 10

2.Solve the system using any method
x + y = 1.7
4x + y = 0.8

3.On a team, 8 girls and 6 boys scored a total of 64 points. The difference between the number of points scored by the 8 girls and the number of points scored by the 6 boys is 16. Each girl scored the same number of points and each boy scored the same number of points. Find the number of points scored by each girl and each boy.

4.Sovle the system of equation by the addition method
{2x = 2y + 5
{-6x + 3y = -30

5.Sovle the system by either the addition method or the substitution method
{ 4y = 5x + 20
{3x - 4y = -20

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