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Warm up 8/24. Solve each equation for y . 1. 7 x + 2 y = 6 2. 3. If 3 x = 4 y + 12, find y when x = 0. 4. If a line passes through (–5, 0) and (0, 2), then it passes through all but which quadrant. y = –2 x – 8. y = –3. IV. Be seated before the bell rings. DESK.
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Warm up 8/24 Solve each equation for y. 1. 7x + 2y = 6 2. 3. If 3x = 4y + 12, find y when x = 0. 4. If a line passes through (–5, 0) and (0, 2), then it passes through all but which quadrant. y = –2x – 8 y = –3 IV
Be seated before the bell rings DESK Warm-up (in your notes) Agenda: Warmup Go over hw p. 94 & 100 Note 2.3 & 2.4 notes homework • Quiz – Tuesday 8/12 • Tomorrow
Notebook 1 Table of content 2.3 Graph linear function/ 2.4 Writing linear functions Page 1) 1-1 Sets of Numbers /1.2 Properties of Numbers 1 2) 1-3 Square Roots 3) 1-4 Simplify Algebra Expression 4) 1.6 Relations/1.7 functions 5) 1.9 Parent Functions 6) 2.1 Linear Equations/ 2.2 Proportions 7) 2.3 & 2.4
2.3 Graph & (2.4) write linear functions Learning targets • 2.3: I can graph linear equations using slope and a point • 2.3: I can graph linear equations using intercepts • 2.3: I can graph linear equations in slope-intercept form • 2.4: I can write the equation of a line in slope intercept form • 2.4: I can write the equation of parallel and perpendicular lines in slope-intercept form
2.3 Graph & (2.4) write linear functions How much do you know Write down as many word as you can about linear functions. ______________ ______________ ______________ ______________ ______________ ______________
2.3 Graph & (2.4) write linear functions Functions 𝟏, 𝟐, and 𝟑 have the tables shown below. Examine each of them, make a conjecture about which will be linear, and justify your claim.
+2 +2 +2 2.3 Graph & (2.4) write linear functions –1 –1 –1 A linear function has a constant rate of change constant rate of change = Slope (m)
Graphing Linear Functions 3 ways to graph: • With y-intercept and slope • With a point and a slope • With x and y-intercepts
Slope-Intercept Form: y=mx+b 1st way Example: y=-3/4x+3
Point & Slope: has a slope m and passes through the point (x,y) 2nd Way Example: slope of 3/2 and goes through (2,2)
Intercepts: Find the intercepts and graph. To find y-intercept: plug in 0 for x To find x-intercept: plug in 0 for y 3rd way Example: y=-x+2 y-intercept: y=-(0)+2 y=2 x-intercept: (0)=-x+2 2=x
Use: y=mx+bory-y1= m(x-x1)b 2.4 Writing equations Slope (m) Slope (m) Point (x1, y1)b y-intercept
You try! Find equation of line given two points (–2, 2) and (2, –4) in point slope form.
Parallel Lines have ___ ___ ____ OUT ___ ___ ____ ______ Slope the same
Perpendicular Lines have _N__ ___ ____ ____ ____ ___ ____ ____ OUT ___ ___ ___ ___ ___ ___ ___ ___ ____ ___ _____ Slope Negative Reciprocals
Parallel and perpendicular lines Perpendicular Parallel Same slope Opposite reciprocal
Parallel Line: Have the same slopes Parallel Line: Perpendicular Line: Have negative reciprocal slopes Perpendicular Line: negative reciprocal
Are the two lines Parallel or Perpendicular? y= mx + b slope Rewrite in y = mx+ b -2x-2x 4y = -2x +9 4 4 4 Parallel Lines
Are the two lines Parallel or Perpendicular? y= mx + b slope Rewrite in y = mx+ b -4-4 X - 4 = -5y -5 -5 -5 Neither Lines
Are the two lines Parallel or Perpendicular? y= mx + b slope Perpendicular Lines
Write the equation of Parallel line in the form y= mx + b Example 1: Write the equation of a line that is parallel to y = -4x + 3 that contains P(1,-2). -4 P(1,-2) Step 1: Find slope and a point Step 1: Step 2: Substitute slope and the point into the point-slope form equation. Step 2: -2 -4 1 Step 3: Rewrite in y = mx + b form. Step 3:
Perpendicular Lines in the form y= mx + b Example 1: Write the equation of a line that is perpendicular to to y = -3x -5 that contains P(-3,7). 3 P(-3,7) Steps1: Find slope and a point Steps1: 1 m= Steps2: Substitute slope and the point into the point-slope form equation. Steps2: 1/3 7 -3 Steps3: Rewrite in y = mx + b form. Steps3:
You try! Example Write the equation of the line in slope-intercept form. parallel to y = 5x – 3 and through (1, 4) m = 5 Parallel lines have equal slopes. Use y – y1 = m(x – x1) with (x1, y1) = (5, 2). y –4 = 5(x – 1) y – 4 = 5x – 5 Distributive property. y= 5x – 1 Simplify.
The slope of the given line is , so the slope of the perpendicular, line is the opposite reciprocal . You try Write the equation of the line in slope-intercept form. perpendicular toand through (0, –2) Use y – y1 = m(x – x1). y + 2 is equivalent to y – (–2). Distributive property. Simplify.
Summarize: In 10 words are less summarize the what you learned. Shared with your group which concept today will most likely appear on the test.