Question

помогите пожалуйста срочно​

Answer 1

$\displaystyle\bf\\x^{2} +5x+6=0\\\\Teorema \ Vieta:\\\\x_{1} +x_{2} =-5\\\\x_{1} \cdot x_{2} =6\\\\(x_{1} +x_{2} )^{2} =(-5)^{2} \\\\x_{1} ^{2} +2\cdot x_{1} x_{2} +x_{2} ^{2} =25\\\\x_{1} ^{2} +x_{2} ^{2} =25-2\cdot x_{1} x_{2} =25-2\cdot 6=25-12=13\\\\\boxed{x_{1} ^{2} +x_{2} ^{2} =13}$