Quadratic & Other Test 2

 In a plane, P and Q are two points having co-ordinate (3, 0) and (6, 4) respectively. Then the numerical value of the circumference of circle with radius PQ is:

Find a quadratic equation in x whose roots are 5 and 6.

 The range  of values of m for which the roots of the equation 3x² + 2x + m(m − 1) = 0 are of opposite sign?

If b and c are the roots of the equation x² + bx + c = 0 then.

 If (x + y - z)² + (y + z - x)² + (z + x - y)² = 0, then the value of x + y - z is?