[tex]\displaystyle\bf\\1)\\\\-5x^{2} +10x-15=0 \ |:(-5)\\\\x^{2} -2x+3=0\\\\Teorema \ Vieta \ :\\x_{1} + x_{2} =2\\\\x_{1} \cdot x_{2} =3\\\\\\\frac{1}{x_{1} } +\frac{1}{x_{2} } =\frac{x_{1} +x_{2} }{x_{1}\cdot x_{2} } =\frac{2}{3} \\\\\\x_{1} x_{2} ^{2} +x_{2} x_{1}^{2} =x_{1} \cdot x_{2} \cdot(x_{1} +x_{2} )=3\cdot 2=6[/tex]

[tex]\displaystyle\bf\\2)\\\\2x^{2} -3x-+11=0 \ |:2\\\\x^{2} -1,5x+5,5=0\\\\Teorema \ Vieta \ :\\x_{1} + x_{2} =1,5\\\\x_{1} \cdot x_{2} =5,5\\\\\\\frac{1}{x_{1} } +\frac{1}{x_{2} } =\frac{x_{1} +x_{2} }{x_{1}\cdot x_{2} } =\frac{1,5}{5,5} =\frac{3}{11} \\\\\\x_{1} x_{2} ^{2} +x_{2} x_{1}^{2} =x_{1} \cdot x_{2} \cdot(x_{1} +x_{2} )=5,5\cdot 1,5=8,25[/tex]