
Given
x2 (dy/dx) = y2 + 2xy
=> dy/dx = y2 /x2 + 2xy/x2
=> dy/dx = y2 /x2 + 2y/x ..............1
Now Let y = vx
=> dy/dx = v + x*(dvdx)
From equation 1, we get
v + x*(dv/dx) = v2 + 2v
=> x*(dv/dx) = v2 + 2v - v
=> x*(dv/dx) = v2 + v
=> dv/(v2 + v) = dx/x
=> dv/v(v + 1) = dx/x .............2
Now,
1/v(v + 1) = A/v + B/(v+1) {using partial fraction}
=> 1/v(v + 1) = {A(v+1) + Bv}/v(v+1)
=> 1 = A(v+1) + Bv
=> 1 = Av + A + Bv
=> 1 = (A+B)v + A
=> A = 1 and A + B = 0
=> A = 1 and B = -1
Now,
1/v(v + 1) = 1/v - 1/(v+1)
From equation 2, we get
{1/v - 1/(v+1)}dv = dx/x
=> dv/v - dv/(v+1) = dx/x
Integrate on both side, we get
∫dv/v - ∫dv/(v+1) = ∫dx/x
=> logv - log(v+1) = logx + logc {logc is a constant}
=> log(v/v+1) = logcx
=> cx = v/(v+1)
=> cx = (y/x)/(y/x + 1)
=> cx = (y/x)/{(y + x)/x}
=> cx = y/(y + x)
=> y = cx(y + x)