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Check to see if coefficients of x are equal. Parallel Lines Are two lines parallel? Do they have the same gradient? m1 = m2 To find out if two lines are parallel put in the form y = mx + b Check to see if coefficients of x are equal. GeoGebra

Are the two lines parallel? Parallel Lines Are the two lines parallel? 10x + 2y - 7 = 0 5x + y - 3 = 0 y - 3 = -5x 2y - 7 = -10x y = -5x + 3 2y = -10x + 7 y = -5x + 3.5 m1 = -5 m2 = -5 They are parallel !

Are the two lines parallel? Parallel Lines Are the two lines parallel? 6x + 2y - 3 = 0 3x + y - 3 = 0 y - 3 = -3x 2y - 3 = -6x y = -3x + 3 2y = -6x + 3 y = -2x + 1.5 m1 = -2 m2 = -3 They are NOT parallel !

Are the interval and line parallel? Parallel Lines Are the interval and line parallel? (2,3) to (5,9) 4x + 2y - 6 = 0 y2 – y1 x2 - x1 2y - 6 = -4x m = 4y = -8x + 6 9 – 3 5 - 2 = y = -2x + 1.5 m1 = 2 m2 = -2 They are NOT parallel !

Are the interval and line parallel? Parallel Lines Are the interval and line parallel? (2,9) to (5,3) 6x + 3y - 5 = 0 y2 – y1 x2-x1 3y - 5 = -6x m = 4y = -8x + 5 3 – 9 5 - 2 = y = -2x + 1.25 m1 = -2 m2 = -2 They are parallel !