[tex]k^2-8k+20=8[/tex][tex]k^2-8k+12=0[/tex][tex]k^2-8k=-12[/tex][tex]k^2-8k+16=-12+16[/tex][tex](k-4)^2=4[/tex]
then k-4=2 or k-4=-2
and we have that k=6 and k=2, are the two answers for the equation.
if we replace k=2 in the first equation
[tex](2)^2-8(2)+20=4-16+20=-12+20=8[/tex]
which makes the equation true for k=2, then is we replace k=6 in the first equation:
[tex](6)^2-8(6)+20=36-48+20=-12+20=8[/tex]
then the equation holds for k=6 too.
the second equation is:
[tex]2=\sqrt[]{-4-x}[/tex]
then
[tex]4=-4-x[/tex][tex]x=-4-4[/tex]
finally
[tex]x=-8[/tex]
if we replace x=-8 in the second equation
[tex]\sqrt[]{-4-(-8)}=\sqrt[]{-4+8}=\sqrt[]{4}=2[/tex]
then the equation holds for x=-8.
