The given functions are $f(x) = 5x + 7$ and $g(x) = \frac{4}{x - 3}$, with $x \ne 3$.
(a(i))[2]
Calculate $fg(1)$.
(a(ii))[2]
Calculate $gf(x)$.
(a(iii))[3]
Calculate $g^{-1}(x)$.
(a(iv))[1]
Calculate $f^{-1}(2)$.
(b(i))[3]
Show that the equation becomes $5x^2 - 8x - 25 = 0$.
(b(ii))[4]
Solve $5x^2 - 8x - 25 = 0$. Show your full working and write your answers to 2 decimal places.
Worked solution & mark scheme
This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: “So the value is $-3$.” …
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