Question

помогите пожалуйста .... прошу​

Answer 1

$7x^{2} +28x-(x+4)=0\\\\7x^{2}+28x-x-4=0\\\\7x^{2} +27x-4=0\\\\D=(27)^{2}-4*7*(-4)=729+112=841=29^{2}\\\\x_{1} =\frac{-27-29}{14} =\frac{-56}{14}=-4\\\\x_{2}=\frac{-27+29}{14}=\frac{2}{14}=\frac{1}{7}\\\\Otvet:\boxed{x_{1}=-4 \ ; \ x_{2}=\frac{1}{7}}$