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Find the slope of a line perpendicular to 2y= -8x +8

Find the slope of a line perpendicular to 2y= -8x +8-example-1
User Mcmaloney
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Re-arrange the equation 4y - 3x = 8 in the form y = mx + cy = 3/4x +2The gradient is 3/4Now we need to work out the gradient of the 2nd line. Remember that when 2 lines are perpendicular the product of their gradients is -1. Let's call the gradient of the second line m.3/4m = -1m = -4/3In the question we are told that the line passes through the point (0, 2). This means that the line crosses the y axis at +2.So the equation of the line that is perpendicular to 4y - 3x = 8 is y = - 4/3x + 2Finding the gradient of a line between two pointsTo find the gradient of a line we need to know how many it goes up, for every one across.ExampleFind the gradient of the line joining (1,3) to (4,9).As we go from (1,3) to (4,9) the y value increases by 6, and the x value increases by 3. So the line goes 6 up for 3 across. So this line has a gradient of 6/3 = 2.Use this technique to answer the following question:QuestionLine A goes through the points (4, 9) and (1, 3). Find the perpendicular line through the point (2, 0).
User Josh Heald
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