Question

Число -5 є коренем рівняння ​

Answer 1

$\displaystyle\bf\\2x^{2} +9x+c=0\\\\x_{1} -5\\\\2\cdot (-5)^{2} +9\cdot(-5)+c=0\\\\2\cdot 25-45+c=0\\\\50-45+c=0\\\\5+c=0\\\\\boxed{\boxed{c=-5}}\\\\\\2x^{2} +9x-5=0\\\\Teorema \ Vieta:\\x_{1} +x_{2} =\frac{-9}{2} \\\\x_{1} +x_{2} =-4,5\\\\x_{2} =-4,5-x_{1} =-4,5-(-5)=-4,5+5=0,5\\\\\boxed{\boxed{x_{2} =0,5}}$