Which of the following is a quadratic equation?

Choose the correct alternative from those given below each question: Which of the following is quadratic equation?

Which of the following is quadratic equation ?

Which of the following is quadratic equation: x^2=x

Which of the following is the quadratic equation whose roots are cosec^(2) theta and sec^(2) theta when θ = π/ 4?

Which of the following is quadratic equation: (x-1)^2=x-1

Which of the following are quadratic equations? (x+2)^(2)=2x^(2)

Which of the following are quadratic equations? x^(2)+2x+11=0

Which of the following are quadratic equations? x^(2)+2x+11=0

Which of the following is quadratic equation: x-1/x=0

Which of the following is quadratic equation: x^2+1/x=0