Equation of Tangent

[vjc]

Thanks a lot roadrunner. Works flawlessly now. I had spent so much time on it but with my limited knowledge could not figure it out. Thanks a ton.

The answer that I am getting shows the -ve B as:
y=3x+-4 instead of y=3x-4
and if I modify "X +" in the last line of program to just "X " I get the - values correctly but if there is a positive value of B there is no + sign (I get 3x4 instead of 3x+4).

I can live with y=3x+-4 as I do get the answer but is there a way where I could either + or - sign before B as appropriate.

And many thanks once again roadrunner.