x2-4x=3x-2+28=3x+26,
x2-7x-26=0 or x2-7x=26, so complete the square:
x2-7x+49/4=26+49/4=153/4,
(x-7/2)2=153/4,
x-7/2=±√153/2=±√(9×17)/2=±(3/2)√17,
x=7/2±(3/2)√17=9.6847 or -2.6847 approx.
If this is a geometry question and x is the length of a side or line segment, then we must choose the positive value x=9.6847.