\[4x² - 15x + 9 = 0\]
\[D = 225 - 144 = 81\]
\[x_{1} = \frac{15 + 9}{8} = \frac{24}{8} = 3;\ \ \ \]
\[x_{2} = \frac{15 - 9}{8} = \frac{6}{8} = \frac{3}{4};\]
\[4x^{2} - 15x + 9 = 4 \cdot (x - 3)\left( x - \frac{3}{4} \right) =\]
\[= (x - 3)(4x - 3).\]