Expand the squared binomials:
[tex](2x+4)^2=4x^2+16x+16[/tex]
[tex](x-5)^2=x^2-10x+25[/tex]
Then
[tex](4x^2+16x+16)-(x^2-10x+25)=3x^2+26x-9=26x[/tex]
[tex]\implies3x^2-9=0[/tex]
[tex]\implies3x^2=9[/tex]
[tex]\implies x^2=3[/tex]
[tex]\implies x=\pm\sqrt3[/tex]
