OG详解-OG1 数学1 Q14

The correct answer is either 2 or -12. The left-hand side of the given equation can be rewritten by factoring. The two values that multiply to -24 and add to 10 are 12 and -2. It follows that the given equation can be rewritten as (z+12 )( z-2 ) = 0 . Setting each factor equal to 0 yields two equations: z + 12 = 0 and z -2=0. Subtracting 12 from both sides of the equation z + 12 = 0 results in z = -12. Adding 2 to both sides of the equation z - 2 = 0 results in z =2. Note that 2 and -12 are examples of ways to enter a correct answer.