Question

x(x-2)=2(x+6) me ajudem por favor a resolver essa equação

Answer 1

$x(x-2)=2(x+6)\to\\\\\\ x^{2} -2x=2x+12\to \\\\ x^{2} -2x-2x-12=0\to \\\\ x^{2} -4x-12=0\\\\ a=1;b=-4;c=-12\\\\\\ \Delta=b^2-4ac\to \Delta=(-4)^2-4*1*(-12)\to \Delta=16+48\to \Delta=64\\\\ x' \neq x''\\\\\\ x= \frac{-b \pm \sqrt{\Delta} }{2a} \to x= \frac{-(-4) \pm \sqrt{64} }{2*1} \to x= \frac{4 \pm8 }{2} \to \\\\\\ x'= \frac{4 +8 }{2} \to x'= \frac{12 }{2} \to x'=6\\\\\\ x''= \frac{4 -8 }{2} \to x''= \frac{-4 }{2} \to x''=-2\\\\\\\\ S=(-2;6)$