The roots of $a{x^2} + bx + c = 0$ ,where $a \ne 0$ ,b,c

are non-real complex and

$a + c < b$ , then

If $(x^{2}-2)+(y+3)i=7+4i$  then x and y are 

Let $P(e^{i\theta_1})$, $Q(e^{i\theta_2})$ and $R(e^{i\theta_3})$ be the vertices of a triangle PQR in the Argand Plane. The orthocenter of the triangle PQR is

If $(2 - i)\times(a - bi) = 2 + 9i$, where i is the imaginary unit and a and b are real numbers, then a equals