Chapter 6 - Systems of Equations and Inequalities - 6-1 Solving Systems by Graphing - Practice and Problem-Solving Exercises - Page 364: 39

16 weeks

account 1: (0, 40) and (4,50) $m = (50-40)/(4-0)$ $m = 10/4 = 5/2$ $y= mx+b$ $40 = 5/2*0+b$ $40 = 0 + b$ $40 = b$ $y=5/2*x+40$ account 2: (0,0) and (2,10) $m = (10-0)/(2-0)$ $m = 10/2 = 5$ $y= mx+b$ $0= 5*0+b$ $0 = 0 + b$ $0 = b$ $y=5x$ $5/2*x+40 = 5x$ $5/2*x+40-5/2*x= 5x-5/2*x$ $40 = 5/2*x$ $40*2/5 = 5/2*x*2/5$ $16= x $