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Hi Daphne. Here's a similar problem to yours and how I solve it: Question. What is the equation of the line perpendicular to  9x + 2y = 20 which passes through (8,1)? Answer. The slopes of perpendicular lines have slopes that are the negative reciprocal of each other. When a line equation is in Ax + By = C form (as the one above is), then the slope is m = A/B. So the perpendicular slope is B/A. Therefore, we can just swap the constants and change one of the signs! This means the equation of any line perpendicular to this one is 2x + 9y = ?. "A" was replaced with "B" and "B" was replaced with "A". Now I simply plug in the (x,y) value I was given to finish it off: 2(8) + 9(1) = 7. So the answer is 2x + 9y = 7. Now you try your problem. Cheers,  


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