Science:Math Exam Resources/Courses/MATH100/December 2016/Question 04 (a)/Hint 1

A line is tangent to the function $y=f(x)$ at $x=a$, if first the tangency point lies on both the line and the function, and also the slope of the line is the derivative of the function at $x=a$. Therefore,

a function is tangent to the given line if it goes through $(1,6)$ and has derivative $4$ at that point.