Question

Решите уровнение 2)х2-5х-4=10;

Answer 1

$x^{2} -5x-4=10;\\x^{2} -5x-4-10=0;\\x^{2} -5x-14=0;\\D=(-5)^{2} -4*1*(-14)=25+56=81=9^{2} ;\\x_{1} =\dfrac{5-9}{2} =\dfrac{-4}{2} =-2;\\x_{2} =\dfrac{5+9}{2} =\dfrac{14}{2} =7.$