Mathematics - Functions Question with Solution | TestHub

At $x=11$

$3f(11\grave{y}+2f(7)=140$

but $x=7$ to get

$3f(7)+2f(11)=100$

$\frac{(1)}{(2)}\Rightarrow \frac{3f(1)+2f(7)}{3f(7)-2f(11)}=\frac{7}{5}$

Using componendo and dividendo $\frac{5(f(1)+f(7))}{(f(11)-f(7))}=\frac{6}{1}\Rightarrow \frac{(f(11)+f(7))}{(f(11)-f(7))}=\frac{6}{5}$ $\frac{f(11)}{f(7)}=11$