i think it's nicer to use , but if you must use y = mx + b, that's fine.

you start by finding the derivative of f(x), this gives a formula for the slope at any x. this will give you the value for m.Find the equation of the line tangent to the graph of the given function at the point with the indicated x coordinate.

f(x) = x/(x^2 + 1); x=1

afterwards, you need to find corresponding x and y values. you were already given the x-value. to find the y-value, plug in the given x-value into the original equation and solve for y (which is the same as f(x)). then plug in all those values into y = mx + b. b will be your only unknown, solve for it. then rewrite the equation y = mx + b, filling in only m and b, that will be the tangent line

try it and see what you get