# Linear Equations Basics: Slope Intercept Form

In this lesson on linear equations, Matty Lu and Mc Welch cover the basics of the slope intercept form, which is used to graph linear equations. The formula for slope intercept form

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## About Linear Equations Basics: Slope Intercept Form

PowerPoint presentation about 'Linear Equations Basics: Slope Intercept Form'. This presentation describes the topic on In this lesson on linear equations, Matty Lu and Mc Welch cover the basics of the slope intercept form, which is used to graph linear equations. The formula for slope intercept form. The key topics included in this slideshow are . Download this presentation absolutely free.

## Presentation Transcript

Slide1Linear EquationsBy Matty Lu and Mc-Welch

Slide2Basics• Slope-Intercept Form y =  m x +  b m  = slope b  = y-intercept Ex.    y =  2/3 x +  2   slope = 2/3 y-intercept = 2

Slide3Slopey =  m x + b slope=  rise/run slope  =   y   =   y2-y1                x      x2-x1 Ex. (-3,0) (3,4)  slope=  4 - 0   =   2             3-(-3)      3

Slide4y-intercepty = mx +  b b  = x-value at which line crosses y-axis 1. Plug in coordinates for x and y 2. Plug in slope for  m 3. Solve for  b Ex. (3,4)  m = 2/3 y =  m x +  b 4=( 2/3 )(3) +  b 4 = 2 +  b 2 =  b

Slide5Example 1Write in slope-intercept form the equation of the line that passes through the given points. Ex. 1.   (6,2) , (8,-4) Step 1   -4 –2  =   -3              8 - 6 Step 2 y =  m x +  b 2 = ( -3 )6 +  b b  = 20 Final Step y =  m x +  b y =  -3 x +  20

Slide6Example 2Using the graph, identify  y-intercept  and  slope and put into slope-intercept form y-intercept  = 1 slope  = -4 y =  -4 x +  1

Slide7Example 3Between 1995-2001, a company’s profits decreased by about \$1200 per year. In 1997, the company had an annual profit of \$1,500,000. Write an equation that gives the annual profit  P  in terms of the year  t.  Let t =0 represent 1995.

Slide8Example 3 (cont.)Step 1:   Identify key values •  x = years ( t )   y = \$profit ( P) •   slope  = -\$1200/yr •  point  (2, 1500000) with 2 representing the year 1997 Step 2: Substitute values into equation, and solve for  b y =  m x +  b 1500000 = ( -1200 )(2) +  b b  = 1502400 Step 3: Write equation y =  m x +  b y =  -1200 x +  1502400

Slide9Extra ProblemsWrite equation using the given information. 1. m = 4,  b = -2 2. m = -5,  b = 3 3. (2, 6),  m = 2 4. (3, -9),  m = -5 5. (-2, 5),  (2, 4) 6. (9, -1),  (1, -9) Click for the answers. 1. y = 4x – 2 2. y = -5x + 3 3. y = 2x + 2 4. y = -5x + 6 5. y = -1/4x + 9/2 6. y = x – 10

Slide10Website Links - explanations• For additional practice go to the following website,  www.classzone.com .