a. Rewrite the equation in a rotated $x^{\prime} y^{\prime}$ -system without an $x^{\prime} y^{\prime}$ -term. Use the appropriate rotation formulas from Exercises $7-18$
b. Express the equation involving $x^{\prime}$ and $y^{\prime}$ in the standard form of a conic section.
c. Use the rotated system to graph the equation.
$$3 x y-4 y^{2}+18=0$$