text: equations of lines, passing though (perpendicular & parallel to) (-1,5) 2x+4y=1? is this correct...  y-5=1/2(x-(-1)) y=1/2x+2 y=1/2x+3/2 (parallel)  y-5=-2(x-5) y=-2x+5 (perpendicular)  thank you! first we put the equation 2x+4y=1 into slope-intercept form.  4y = -2x + 1 y = -1/2x + 1/4 the slope is -1/2.  then using point-slope form, we find parallel equation through (-1,5): x1 is -1 and y1 is 5 (y-y1) = m(x-x1) y-5 = -1/2(x--1) y-5 = -1/2(x+1) y-5 = -1/2x - 1/2 y-10/2 = -1/2x - 1/2 y = -1/2x + 9/2  then using point-slope form, we find perpendicular equation through (-1,5) with slope 2.  to get the perpendicular slope, you take the negative reciprocal.  again, x1 is -1 and y1 is 5. (y-y1) = m(x-x1) y-5 = 2(x--1) y-5 = 2(x+1) y-5 = 2x + 2 y = 2x + 7