[tex]\frac{x+1}{3} = \frac{x+5}{x} \\ \\ 3(x+5)=x(x+1) \\ \\ 3x+15=x^2+x \\ \\ 3x+15-x^2-x=0 \\ \\ -x^2+2x+15=0 \\ \\ \boxed{\boxed{ \Delta=b^2-4ac}} \\ \\ \Delta=2^2-4\cdot(-1)\cdot15 \\ \Delta=4+60\\ \Delta=64 \\ \\ \boxed{\boxed{\text{X}_{1,2}= \frac{-b\pm \sqrt{\Delta} }{2a} }} \\ \\ \\ \boxed{\text{X}_{1}= \frac{-b - \sqrt{\Delta} }{2a} = \frac{-2-8}{-2} = \frac{10}{2} = 5} \\ \boxed{\text{X}_2= \frac{-b+ \sqrt{\Delta} }{2a} = \frac{-2+8}{-2} = \frac{6}{2}=3 } [/tex]
