Question

3xelevado a 2+5x=2x elevado a 2 -9-x

Answer 1

$3 x^{2} +5x=2 x^{2} -9-x\\\\\\ 3 x^{2} +5x-2 x^{2}+9+x=0\to \\\\ x^{2} +6x+9=0\\\\ a=1;b=6;c=9\\\\\\ \Delta=b^2-4ac\to \Delta=6^2-4*1*9\to \Delta=36-36\to \Delta=0\\\\\\ x'=x''\\\\\\ x= \frac{-b \pm \sqrt{ \Delta} }{2a} \to x= \frac{-6 \pm \sqrt{0} }{2*1} \to x= \frac{-6 \pm 0 }{2} \to \\\\\\ x'=x''= \frac{-6 }{2} \to x'=x''=-3\\\\\\\\ S=(-3)$