Concept:Solving a quadratic equation by factorisation.Explanation:We need two numbers whose product is −3 and whose sum is −2.These numbers are −3 and 1.So, x2−2x−3=(x−3)(x+1)=0.Using the zero product property:x−3=0 or x+1=0.Therefore, x=3 or x=−1.Answer:x=3 or x=−1.