5-7 AX + BY = C FORM MISS BATTAGLIA – ALGEBRA 1 CP OBJECTIVE: GRAPH EQUATIONS USING X- AND Y- INTERCEPTS; WRITE EQUATIONS IN AX+BY=C FORM; MODEL SITUATIONS WITH EQUATIONS IN THE FORM AX+BY=C.

WARM UP The choir director offers to stop at a fast food restaurant with 60 students after a performance. A discussion reveals that 35 students like cheeseburgers, 37 like pizza, 36 students like tacos, 22 students like cheeseburgers or pizza, 18 students like pizza or tacos, 23 students like tacos or cheeseburgers, and 15 students like all three choices. How many students like only one of the three fast food choices?

GRAPHING EQUATIONS Ax + By = C Form of a Linear Equation Ax + By = C is a linear equation, where A and B cannot both be zero. 3x + 4y = 8 To make a quick graph, you can use the x- and y-intercepts. The x-intercept is the x-coordinate of the point where a line crosses the x- axis.

GRAPH 3x + 4y = 8 Find the x- and y-intercept

FIND THE X- AND Y-INTERCEPTS OF EACH EQUATION a. 3x + 4y = 12 b. 2x – y = 4

GRAPH ON A GRAPHING CALCULATOR 5x – 3y = 120 Step 1: Write the equation in slope-intercept form. Step 2: Find the x- and y-intercepts. Step 3: Set the ranges to include the x- and y-axes and the intercepts. Then graph!

FITNESS When you jog, you burn 7.3 calories/min. When you run, you burn 11.3 calories/min. Write an equation to find the times you would need to run and job in order to burn 500 calories.

EXAMPLE

HOMEWORK Pg # 1, 4 – 7, 12a, 13, 14a, 20 – 22