The last one You’re completing the square here so you have to find (1/2b)^2. In this case it’s 1. So you have to add 1 to both sides. Then you have to solve for it It becomes (x-1)^2 = -7 Then you have to find the square root (x-1) = √-7 x-1 = √7 √-1 x-1= ± i √7 x= 1 ±i √7 That’s your answer and d is the only one that matches with it
