13. Writing Equations from Graphs Use the graph of f(x) = |x to write an equation for each function whose graph is shown. (a) (b ) - X -2 -4 14. Writing Equations from Graphs Use the graph of f(x) = vx to write an equation for each function whose graph is shown. (a) y (b) 2+ -x 2 4 6 8 10 * x -4 -2 2 4 6 -4- -8 -8-- -10+ -10+