Question

Решите систему :
9х^2-14х=у
9х-14=у

Answer 1

$left { {{9x^2-14x=y} atop {9x-14=y}} right. \ \ 9x^2-9x-14x+14=0 \ \ 9x^2-23x+14=0 \ \ D=b^2-4ac=(-23)^2-4*9*14=529-504=25 \ \ x_{1} = frac{-b+ sqrt{D} }{2a} =frac{23+5}{2*9} = frac{28}{18}= frac{14}{9} =1 frac{5}{9} \ \ x_{2} = frac{-b- sqrt{D} }{2a} =frac{23-5}{2*9} = frac{18}{18} =1 \ \ y_{1}=9*frac{14}{9}-14=0 \ \ y_{2}=9*1-14=-5$