Check if the relation given by the equation represents $y$ as function of $x$.

$3x-6=21$

If $f\left(m\right)=m^2-3m+1$, find $f\left(0\right)$

If $f\left(m\right)=m^2-3m+1$, then find the value of $f\left(-3\right)$.

If $f\left(m\right)=m^2-3m+1$, then find $f\left(\frac{1}{2}\right)$.

If $f\left(m\right)=m^2-3m+1$ and $f\left(x+1\right)=x^2-x-k$, then find the value of $k$.

If $f\left(m\right)=m^2-3m+1$ and $f\left(-x\right)=x^2+kx+1$, then what is the value of $k?$

If $f\left(m\right)=m^2-3m+1$, if $\left(\frac{f(2+h)-f\left(2\right)}{h}\right)=h+p, h\ne 0$, find the value of $p$

Find $x$, if $g\left(x\right)=0$ where $g\left(x\right)=\frac{5x-6}{7}$

Find sum of possible values of $x$, if $g\left(x\right)=0$ where $g\left(x\right)=\frac{18-2x^2}{7}$