Determine the equation of the line which is perpendicular to y = 2x + 9 and crosses through the point (1,2)
When multiplied together the gradients of perpendicular lines should give the answer - 1So: x1x2 = -1x1 = 2 x2 = -1/2It crosses through the point (1,2)y = ax+ ba = -1/2y = 22 = -1/2 + bb = 5/2so the equation of the line is y = -1/2x + 5/2
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