a) The function f+g is just the sum of the 2 functions f and g.
The derivative of f+g is also just the sum of the derivatives.
So to find slope of new tangent line, you find sum of the slopes for f and g.
---> m = 2+2 = 4
The point on new curve is (4, f(4)+g(4)) -----> (4,17)
The equation of tangent line is then:
y - 17 = 4(x -4)
y = 4x + 1
b) and c) are done the same way. f-g means subtract slopes.
2f means double slope etc...