How to Solve Quadratic Equations Unit Test?

For the question number 1,
x2-4x+4=0
x2-2*x*2+2^2=0
Comparing the above equation with x2-2xy+y2=0, the perfect square factor is (x-y)2
so the perfect square factor of the question is (x-2)2

For the question number 2,
First, we need to find the factors of the constant term. The factors are 1, 2, 3 and 6. We need to add or subtract according to the sign of the constant term. When negative term, we have to subtract and when positive we have to add. So we need to subtract its factors and make 5. So, the factors 6 and 1 are suitable. Then,
x2-(6x-x)-6=0
x2-6x+x-6=0
x(x-6)+1(x-6)=0
(x-6)(x+1)=0
So the factors are given above.