Which graph represents exponential decay? On a coordinate plane, a straight line has a negative slope. On a coordinate plane, a graph starts at (negative 2, 0) and curves up and to the right into quadrant 1. On a coordinate plane, a graph approaches y = 0 in quadrant 1 and curves up into quadrant 2. On a coordinate plane, a graph approaches y = 0 in quadrant 2 and curves up into quadrant 1.