determinant \[ \left |\begin{array}{cccc} 1 &6 & 9 \7 &90 & f(x) \9 & \psi(x) &g(x) \\end{array}\right| \]
$$\left |\ begin{array}{cccc}1 &6 & 9 \7 &90 & f(x) \9 & \psi(x) &g(x) \\end{array}\
determinant \[ \left |\begin{array}{cccc} 1 &6 & 9 \7 &90 & f(x) \9 & \psi(x) &g(x) \\end{array}\right| \]
$$\left |\ begin{array}{cccc}1 &6 & 9 \7 &90 & f(x) \9 & \psi(x) &g(x) \\end{array}\