Step 1: For circle
\[
S=x^2+y^2+2gx+2fy+c=0
\]
length of tangent from \((x_1,y_1)\) is:
\[
\sqrt{S_1}
\]
Step 2: Substitute \((5,1)\):
\[
S_1=5^2+1^2+6(5)-4(1)-3
\]
\[
=25+1+30-4-3
\]
\[
=49
\]
Step 3: Length of tangent:
\[
\sqrt{49}=7
\]
\[
\boxed{7}
\]