The line in the graph shows a relationship between two variables, x and What is the slope of the curve? The slope of the curve is D. the slope is negative, use a minus sign. If the slope is positive, do not use a plus sign. Solution Slope of the curve is tan theeta P/B = -8/2 = -4 Minus sign is used because the line is downward sloping which means when X increases, Y decreases and vice verca i.e. x and y are inversely correlated..