Straight line and circle question

Line mx-y-2=0 touches the circle x square -8x +y square +10y+1=0 at two points. Find the value of m.
How to find m?
Thanks a lot.

Weird wording of the question... a line can only touch a circle once...

Anyway, they want you you to find 2 values of $m$ for which the line is tangent to the circle. So begin by substituting the eq. of the line into the eq. of the circle. This should leave you with a quadratic with $m$ involved. Now how many times does a tangent line intersect the circle? So how many roots should we expect to get from our quadratic? Hence, what condition does this imply on the discriminant? So, consider the discriminant and you would end up with a quadratic in $m$ which you can solve and obtain your two $m$ values from.

rearrange mx -y -2 = 0 to y= mx -2 , now insert the value of y into second equation, and solve for m ?? then use b^2 - 4ac

Do think a line could touch circle twice, just like a chord in the circle.