JAMB Mathematics 2020 Paper

Concept:Use the given definition of the binary operation to form and solve a quadratic equation.Explanation:The operation is defined as $a \times b = a^b$.Substitute $b = 2$ into the operation rule.So $a \times 2 = a^2$.But the question states that $a \times 2 = 2 - a$.Therefore, equate the two expressions: $a^2 = 2 - a$.Bring all terms to one side: $a^2 + a - 2 = 0$.Factorize the quadratic: $(a + 2)(a - 1) = 0$.Set each factor equal to zero: $a + 2 = 0$ or $a - 1 = 0$.This gives $a = -2$ or $a = 1$.Answer:The possible values are $a = 1$ or $a = -2$, which corresponds to Option A.