The tangent line to the graph of y=f(x) at both x=3 and x=4 is y=-x+5. Which of the following statements must be true?

Question

The function f(x) is the line y=-x+5

f(3)=f(4)

f'(3)=f'(4)

f(x) is not differentiable at x=3 and x=4

None of the above

Answer 1

the slope, -1 = f' is the same