[tex]2x^2+12x=10 \\ 2x^2+12x-10=0 \ \ |:2 \\ x^2+6x-5=0 \\ D=b^2-4ac=6^2-4*1*(-5)=36+20=56 \\ x_{1,2}= \frac{-bб \sqrt{D} }{2a} \\ \\ x_1= \frac{-6- \sqrt{56} }{2}= \frac{-6- 2\sqrt{14} }{2}=\frac{2(-3- \sqrt{14}) }{2}=-3- \sqrt{14} \\ \\ x_2= \frac{-6+ \sqrt{56} }{2}= \frac{-6+ 2\sqrt{14} }{2}=\frac{2(-3+ \sqrt{14}) }{2}=-3+ \sqrt{14} [/tex]
