Question

Знайти суму і добуток:
2x²-6x+9=0
-y +2y²-5=0
За теоремою Вієта

Answer 1

$ax^{2}+bx+c=0\\\\x_{1}+x_{2}=\frac{-b}{a}\\\\x_{1}*x_{2}=\frac{c}{a}\\\\\\1)2x^{2}-6x+9=0\\\\x_{1}+x_{2}=\frac{6}{2}=3\\\\x_{1}*x_{2}=\frac{9}{2}=4,5\\\\\\2)-y+2y^{2}-5=0\\\\2y^{2} -y-5=0\\\\x_{1} +x_{2} =\frac{1}{2} \\\\x_{1} *x_{2} =-\frac{5}{2}=-2,5$