Learn to write it Learn to graph using it Learn to rearrange equations to get it

 This is used to graph a linear function WITHOUT having to use a table.  You may rearrange an equation so that it is in this form.  If you need to write an equation: your job is to do whatever it takes to find the actual numbers for m and b.  IF you have the graph: count the slope, observe the y- intercept

Ex. 1 Write an equation of the line whose slope is and whose y-intercept is –6. Answer:

Ex. 2 Write an equation of the line whose slope is 4 and whose y-intercept is 3. Answer:

Ex. 3 Write an equation of the line shown in the graph. Answer:The equation of the line is

Ex. 4 Write an equation of the line shown in the graph. Answer:

Ex. 5 Graph Answer:

 Remember: Ax + By = C  We want: y = mx + b  Use the standard form to graph by graphing the x and y intercept (cover-up method).  You may have to rearrange the equation to put it into slope-intercept form.

Ex. 6. Graph Answer:

Ex. 7 Graph Answer:

ex 8  Re-write the equation into slope- intercept form: x + y = 3 x + y = 3 Answer: y = -x + 3

 Write the equations in SIF: 1.x = y x + 4y = 2 3.2x – 3y = y = 8 – 4x  Answers: 1.y = x y = -1/4 x + ½ 3.y = 2/3 x + 5/3 4.y = 8/5 – 4/5 x

Health The ideal maximum heart rate for a 25-year- old who is exercising to burn fat is 117 beats per minute. For every 5 years older than 25, that ideal rate drops 3 beats per minute. Write a linear equation to find the ideal maximum heart rate for anyone over 25 who is exercising to burn fat. WordsThe rate drops 3 beats per minute every 5 years, so the rate of change isbeats per minute each year. The ideal maximum heart rate for a 25-year-old is 117 beats per minute.

VariablesLet R = the ideal heart rate. Let a = years older than 25. Equation ideal rate Ideal rate ofyears older for 25- rateequalschangetimes than 25plusyear-old. Ra117 Answer:

Graph the equation. The graph passes through (0, 117) with a slope of Answer:

Find the ideal maximum heart rate for a person exercising to burn fat who is 55 years old. The age 55 is 30 years older than 25. So, Ideal heart rate equation Replace a with 30. Simplify. Answer:The ideal heart rate for a 55-year- old person is 99 beats per minute.

The amount of money spent on Christmas gifts has increased by an average of $150,000 ($0.15 million) per year since Consumers spent $3 million in a.Write a linear equation to find the average amount spent for any year since Answer:where D is the amount of money spent in millions of dollars, and n is the number of years since 1986

The amount of money spent on Christmas gifts has increased by an average of $150,000 ($0.15 million) per year since Consumers spent $3 million in b.Graph the equation. Answer:

The amount of money spent on Christmas gifts has increased by an average of $150,000 ($0.15 million) per year since Consumers spent $3 million in c.Find the amount spent by consumers in Answer:$4.95 million