ans = 
Your value in (i) for f(1.2) is 49020.80113638172, so when you round to 1 decimal, it becomes 49020.8 which in engineering notation is 4.9021e4 because of rounding the right most digit.
You should reread the question to understand why you are not getting 4.9 as answer (hint:question is asking a where f(1.2) = a * 10^n ) :)
syms x
f = exp(9*x); g = log(sqrt(x));
% (i)
f_at_x = subs(f,x,1.2); % evaluates f(x = 1.2) as symbolic
format long % change displasy setting
f_at_x = double(f_at_x) % converts to double (real)
f_at_x_rounded = round(f_at_x,1) % ??? round to 1 decimal place
format bank % change displasy setting
f_at_x_rounded
For part ii, log(x^n) = n*log(x) so both expressions are equivalent
fun1 = @(x) 0.5*log(exp(9*x));
fun2 = @(x) log(exp(4.5*x));
fun1(1.2) == fun2(1.2) % are they equal?
