3.1 Homework Handout The graph of a system of two linear equations is shown. Circle all that apply. No Solution No Solution No Solution Infinitely many solutions Infinitely many solutions Infinitely many solutions Exactly 1 Solution Exactly 1 Solution Exactly 1 Solution Consistent Consistent Consistent Independent Independent Independent Dependent Dependent Dependent Inconsistent Inconsistent Inconsistent Without the use of a graphing calculator, graph the linear system and tell how many solutions it has. If there is exactly one solution, estimate the solution and check it algebraically. x = 5 x + y = 1 y = -­‐5 – x x + 3y = -­‐15 3
x + y = 5 4
3x + 4y = 2 3.1 Homework Handout -­‐4y = 24x + 4 2x – y = 7 y= -­‐6x – 1 y = 2x + 8 1
x + 7y = 2 3
2
x + 4y = 2 3
You are choosing between two long distance phone services. Company A charges $.09 per minute plus a $4 monthly fee. Company B charges $.11 per minute with no monthly fee. a.) Let x be the number of minutes you call long distance in one month, and let y be the total cost of long distance phone service. Write and graph two equations representing the cost of each company’s service. (Use your graphing calculator to help you to graph the functions). b.) Use your graphing calculator to find the point where the graphs intersect. Which customers should choose Company A. Which customers should choose company B?