To find the equation of a line perpendicular to the given line, we need to first find the slope of the given line, using the slope formula:
Because we need to find a line perpendicular to the given line, we need to use the opposite reciprocal of this slope, along with the point that is given.
Using the point (0,0) and the slope 5/4, we apply the formula y=mx + b and we get the equation for the new line: 
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