Formation of Quadratic equation from roots

Q. If one of the roots of a quadratic equation is 5 and its constant term is 165. Then the quadratic equation is :

1. $5x^2+25x+165=0$
2. $3x^2+33x+165=0$
3. $x^2+15x+165=0$
4. $x^2-38x+165=0$

Q. The quadratic equation which has D = 0 and a root as $\frac{1}{10}$ is

1. $x^2-20x-100=0$
2. $x^2-100x-100=0$
3. $100x^2-20x+1=0$
4. $100x^2-20x+100=0$

Q. In the Maths test two students, while solving a quadratic equation, committed the following mistakes:
(i) One of them made a mistake in the constant term and got the roots as 5 and 9.
(ii) Another one committed an error in the coefficient of x and got the roots as 12 and 4.
But, in the meantime, they realised that they are wrong and they managed to get it right jointly. Find the correct quadratic equation.

1. $x^2-44x+14=0$
2. $x^2-14x+48=0$
3. $2x^2+7x-24=0$
4. $3x^2-17x+52=0$