91Ó°ÊÓ

Solve the system of linear equations using the substitution method. \(x+2 y-z=3\) \(2 x+4 y-2 z=6\) \(-x-2 y+z=-6\)

ABSTRACT REASONING If x and y have a positive correlation, and y and z have a negative correlation, then what can you conclude about the correlation between x and z? Explain.

Use a graphing calculator to graph the function and its parent function. Then describe the transformations. \(h(x)=-3|x|-1\)

Use a graphing calculator to graph the function and its parent function. Then describe the transformations. \(f(x)=\frac{3}{4}|x|+1\)

MATHEMATICAL CONNECTIONS Which equation has a graph that is a line passing through the point \((8,-5)\) and is perpendicular to the graph of \(y=-4 x+1\) ? (A) \(y=\frac{1}{4} x-5\) (B) \(y=-4 x+27\) (C) \(y=-\frac{1}{4} x-7\) (D) \(y=\frac{1}{4} x-7\)

Explain when it might be more convenient to use the elimination method than the substitution method to solve a linear system. Give an example to support your claim.

Use a graphing calculator to graph the function and its parent function. Then describe the transformations. \(g(x)=\frac{1}{2} x^2-6\)

Use a graphing calculator to graph the function and its parent function. Then describe the transformations. \(f(x)=4 x^2-3\)

ANALYZING RELATIONSHIPS Data from North American countries show a positive correlation between the number of personal computers per capita and the average life expectancy in the country. a. Does a positive correlation make sense in this situation? Explain. b. Is it reasonable to conclude that giving residents of a country personal computers will lengthen their lives? Explain.

Using what you know about solving linear systems in two and three variables, plan a strategy for how you would solve a system that has four linear equations in four variables.