Question

x (x+3)=70
....................

Answer 1

$x(x+3)=70\ x^2+3x-70=0\ a=1 b=3 c=-70\ D=b^2-4ac=3^2-4*1*(-70)=289=17^2\ x_{1,2}= frac{-3б17}{2*1}= left[begin{array}{c}7\-10end{array}right] .$