Part one:
[tex]x^2-8x=-26[/tex]
Rewrite in the form [tex](x+a)^{2} =b[/tex]
[tex]\left(x-4\right)^2=-10[/tex]
[tex]\mathrm{For\:}f^2\left(x\right)=a\mathrm{\:the\:solutions\:are\:}f\left(x\right)=\sqrt{a},\:-\sqrt{a}[/tex]
Solve [tex]x-4=\sqrt{-10} : x=\sqrt{10} i+4[/tex]
Solve [tex]x-4=\sqrt{-10} : x=-\sqrt{10} i+4[/tex]
[tex]x=\sqrt{10}i+4,\:x=-\sqrt{10}i+4[/tex]
Part two:
[tex]x=\frac{-\left(-8\right)\pm \sqrt{\left(-8\right)^2-4\cdot \:1\cdot \:26}}{2\cdot \:1}[/tex]
Simplify [tex]\sqrt{\left(-8\right)^2-4\cdot \:1\cdot \:26}}: 2\sqrt{10} i[/tex]
[tex]=\frac{-\left(-8\right)\pm \:2\sqrt{10}i}{2\cdot \:1}[/tex]
Separate solutions
[tex]x_1=\frac{-\left(-8\right)+2\sqrt{10}i}{2\cdot \:1},\:x_2=\frac{-\left(-8\right)-2\sqrt{10}i}{2\cdot \:1}[/tex]
[tex]\frac{-(-8)+2\sqrt{10}i }{2*1} :4+\sqrt{10}i[/tex]
[tex]\frac{-(-8)+2\sqrt{10}i }{2*1} :4-\sqrt{10}i[/tex]
[tex]x=4+\sqrt{10}i,\:x=4-\sqrt{10}i[/tex]
