# If f(4x)=12x-7, how do you find f(16.5)?

$42.7$
If we select $x$ such that $4 x = 16.5 , \text{ then, } x = \frac{16.5}{4}$, and,
$f \left(4 \times \frac{16.5}{4}\right) = 12 \times \frac{16.5}{4} - 7$.
$\therefore f \left(16.5\right) = 3 \times 16.5 - 7 = 49.5 - 7 = 42.7$.