Review HomeworkPages 15-17, 22-23, 28

Page 15-171)y=-x+22)y=3x+13)y=-1.5x-34)y=-0.5x+25)y=-⅓x+26)y=-0.5x-57)d8)c 11) b9)f 12) a10) e

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Pages 221)yes. It is not on the line. y-2=0.6(x+3) 12-2=0.6(12+3) 10=9 x2)y-9=2(x-5) or y-5=2(x-3)3)y-3.5=8(x+2.5) or y+0.5=8(x+3)4)y-6=-3(x-2) 5)a) y-1=1(x-1) or y=x5) b) y+4=0.5(x) or y+3=0.5(x-2)5) c) y-1=-2(x-1) or y-3=-2(x)

page 23

6) y-5 = -1(x-5) 10-5=-1(0-5) 5 = 5 correct7a) (3,14180),(28,51780) are the points y-14180=1504(x-3) or y-51780=1504(x-28) or y=1504x + 96687b) average annual sales increase7c) y=1504(20) + 9668 = 39748

Apples, x 0 kg 1.6 kg 4 kg 6.4 kg 8 kg

Bananas, y 5 kg 4 kg 2.5 kg 1 kg 0 kg

Practice

•pages 24, 29-30

page 248

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almonds, a (kg) 8 6 4 2 0

cashews, c (kg) 0 1.5 3 4.5 6

9) same slope 2/3 LINE y= 2/3 x +110)different slopes (1, 2/3, 3/2) NO line11) y=2x-5 14)

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1-2 Parallel ( 평행선 ) and Perpendicular ( 수선 ) Lines

Slopes of Parallel Lines

Parallel lines have the same (or equal) slopes.

If they are both in slope-intercept form then only the y-intercept is different.

Examplesy=2x+6 y-3=4(x+1)y=2x-8 y+2=4(x+9)

Slopes of Perpendicular Lines

Perpendicular lines have slopes which are opposite reciprocals of each other. (-1 x 역수 )

y=2x -2 is perpendicular to all lines y= -½ x + bfor all values of bThe product of the slopes of perpendicular lines is -1.2 • - ½ = -1

Page 34

• If the slopes of both pairs of opposite sides of a quadrilateral are equal then the figure is a parallelogram.

Perpendicular lines

• If all adjacent sides have slopes with a product of -1 the figure is a rectangle. If two adjacent sides have equal length, the figure is also a square.

Examples

• Write an equation of a line that parallel to y=2x + 6 and passes through (1,3).

• same slope y-3=2(x-1), y=2x+1

• Write an equation of a line that perpendicular to y=2x + 1 and passes through (2,2).

• opposite reciprocal slope• y-2= - ½ (x-2) , y = - ½ x+3

Practice page 36

Homework

• Pages 37-38