[tex]\displaystyle\bf\\x_{1} +x_{2} =\frac{2}{3} \\\\x_{1} \cdotx_{2} =-\frac{7}{15} \\\\\\x^{2} -\frac{2}{3}x-\frac{7}{15}=0 \ |\cdot 15\\\\\\\boxed{15x^{2} -10x-7=0}[/tex]