# Parallel Lines **Parallel lines have the same slopes. What is the slope of the line parallel to y = -2x + 4? m = -2.

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Parallel Lines **Parallel lines have the same slopes. What is the slope of the line parallel to y = -2x + 4? m = -2

Graph a line parallel to the given line and through point (0, -1): Slope = 3 5

Write the equation of a line parallel to 2x – 4y = 8 and containing (-1, 4): – 4y = - 2x + 8 y = 1x – 2 2 Slope =1 2 To make sure it goes through the containing point plug in the x and y into the slope formula y = 1/2x +b 4 = ½(-1) + b b = 4.5 Plug in calc y = 1/2x + 4.5 and view table it should contain (-1,4)

12. Parallel 13. Y – 5 = 2/7 (X – 0) Y = 2/5x Y – 5 = 2/7X Y – 3 = 2/5(X – 3) Y = 2/7x + 5 Y = 2/5x – 6/5 +3 Y = 2/5x + 4 1/5

Perpendicular Lines **Perpendicular lines have the opposite reciprocal slopes. Find the slope of the original line. Change the sign and invert the numerator and denominator of the slope. Use that slope to graph your new line and to write the equation of your new line.

Perpendicular Lines What do you know about the slope of perpendicular lines? Perpendicular lines have slopes that are opposite reciprocals! What is the slope of the line perpendicular to y = -2x + 4? m = 1/2

Graph a line perpendicular to the given line and through point (1, 0): Slope =-3 4 Perpendicular Slope=4 3

Write the equation of a line perpendicular to y = -2x + 3 and containing (3, 7): Original Slope= -2 Perpendicular Slope =1 2

Slope= 3 4 y - 4 = -4(x + 1) 3 Perpendicular Slope = -4 3 Write the equation of a line perpendicular to 3x – 4y = 8 and containing (-1, 4): -4y = -3x + 8

Use the point slope formula

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