Question

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Answer 1

$\displaystyle 1)x^2+30x-10=0\\\\ x=\frac{-30б\sqrt{30^2-4*1*(-10)} }{2*1}=\frac{-30б\sqrt{900+40} }{2}=\frac{-30б\sqrt{940} }{2}=\frac{-30б2\sqrt{235} }{2}\\\\ x_{1}=-15-\sqrt{235},x_{2}=-15+\sqrt{235}\\\\ 2) x^2-10=8x\\x^2-10-8x=0\\x^2-8x-10=0\\\\ x=\frac{-(-8)б\sqrt{(-8)^2-4*1*(-10)} }{2*1}=\frac{8б\sqrt{64+40} }{2}=\frac{8б\sqrt{104} }{2}=\frac{8б2\sqrt{26} }{2}\\\\ x_{1}=4-\sqrt{26},x_{2}=4+\sqrt{26}$

Answer 2

$\displaystyle\bf\\1)\\\\x^{2} +30x-10=0\\\\\frac{D}{4} =\Big(\frac{30}{2} \Big)^{2} -(-10)=15^{2} +10=225+10=235\\\\x_{1} =-\frac{30}{2} +\sqrt{235} =-15+\sqrt{235}\\\\x_{2} =-\frac{30}{2} -\sqrt{235} =-15-\sqrt{235}\\\\\\2)\\\\x^{2} -10=8x\\\\x^{2} -8x-10=0\\\\\frac{D}{4} =\Big(\frac{-8}{2} \Big)^{2} -(-10)=16+10=26\\\\x_{1,2} =4\pm \ \sqrt{26}$