Graph paper and a ruler today October 5th, 2011 (A) Graph paper and a ruler today Happy Summer Birthday to: Kristine Baker

Practice with words. Matching 1) 3 less than twice the number of A) 3 – 2b boxes, b 2) 1 more than Benny’s age, b B) 3(b – 1) 3) The difference of 1 and the number C) 2b – 3 of blue marbles, b 4) Three times 1 less than the number D) b – 1 of birthdays, b 5) Twice the number of baskets, b, less E) b + 1 than 3 C E D B A

What is a “system” of two or more equations? A system of equations is a collection of two or more equations with the same set of variables. Ex: -2x + y = 3 2x + y = -1 (-1,1) The solution of a linear system is an ordered pair (x, y) or no solution or infinite number of solutions.

What is the solution to this system of linear equations?

Solving Linear Systems by Graphing The solution to the system is the ordered pair that is true for both equations – the point where the lines meet.

Solving Linear Systems by Graphing What are ways we know how to graph lines? (slope-intercept form/standard form: find intercepts) Pretend you graphed these two lines: What is the solution to this system of linear equations? Why is accuracy important?

Solving Linear Systems by Graphing Solve the linear system by graphing. Check your solution. 1) y = x + 3 y = -2x + 6 (1,4) Check in the table of the calculator.

Solving Linear Systems by Graphing Solve the linear system by graphing. Check your solution. 2) y = ½x + 1 2x + y = 6 (2,2) Check in the table of the calculator.

Solving Linear Systems by Graphing Solve the linear system by graphing. Check your solution. 3) -5x + y = 0 5x + y = 10 (1,5) Check in the table of the calculator.

Solving Linear Systems by Graphing Solve the linear system by graphing. Check your solution. 4) x = 5 + y x – y = 5 Infinite solutions x = 5 + y

Solving Linear Systems by Graphing Solve the linear system by graphing. Check your solution. 5) y = -x + 7 x + y = -2 NO solution

Solving Linear Systems by Graphing Solve the linear system by graphing. Check your solution. 5) y = 4 -x 2x + 3y = 11 Use the calculator only to solve this one. y1 = and y2 = TABLE copy points

Solving Linear System word problems. The next test will have a total of 50 points. Some questions will be 3 points and some 4 points. Which is the correct system of equations to represent this? 4x + 3y = 15 x + y = 50 4x + 3y = 50 x + y = 15

Homework WS