[tex] x^{2} +6x-7=0[/tex]
Solve by formula : [tex] x_{1.2} = \frac{-b+ \sqrt{ x^{2-4ac} } }{2a} [/tex]
[tex]a=1,b=6,c=-7 [/tex]
[tex] x_{1.2} = \frac{(-6)+ \sqrt{ 6^{2}-4(-7) } }{2} [/tex]
[tex] x_{1.2}= \frac{\sqrt{(-6)+ \sqrt{ 6^{2}+28 } } }{2} [/tex]
[tex] x_{1.2} = \frac{(-6)+ \sqrt{36+28 } }{2} [/tex]
[tex] x_{1.2} = \frac{(-6)+ \sqrt{64} }{2} [/tex]
[tex] x_{1.2} = \frac{(-6)+8}{2} [/tex]
First solution:
[tex] x_{1} = \frac{(-6)+8}{2} [/tex]
[tex] x_{1}= \frac{\not 2}{\not 2} [/tex]
[tex] x_{1} =1[/tex]
Second solution:
[tex] x_{2} = \frac{-6-8}{2} [/tex]
[tex] x_{2} =-14:2[/tex]
[tex] x_{2} =-7[/tex]
The answer is: [tex] x_{1} =1[/tex] , [tex] x_{2} =-7[/tex]
