Question

Find an equation of the tangent line to the graph of f(x) = \frac {1} {\sqrt{7 x}} at x = 9

Answer 1

just take f'(x) and plug x =9 in to get the slope of the line. Then calculate f(9) , that is value of y when x =9
now, you have (9, y) and slope
plug all in y = mx +b to find b,
after getting b, put all m, b back to y = mx+b to get the answer