Express each of these formulae in terms of $a$.

$L=Ba+\left(1+C\right)a$

Express each of these formulae in terms of $a$.

$b=\frac{a}{a-5}$

Express each of these formulae in terms of $a$.

$y=\frac{a+x}{a-x}$

You can use the formula $A=\frac{{\mathrm{\pi d}}^2}{4}$ to find the area ($A$) of a circle, where $d$ is the diameter of the circle.

Find the area of a circle of diameter $1.2 m$.

If $g\left(x\right)=\sqrt{4x+1}$ and $g\left(x\right)=5$, find the value of $x$.

For the following pair of functions, evaluate $fg\left(x\right) \& gf\left(x\right)$.

$f\left(x\right)=x+6$

$g\left(x\right)=x-3$

$f\left(x\right)=3x+1$ and $h\left(x\right)=6x^2$, find: $hf(-2)$.

Given $f\left(x\right)=8-x^2 \& g\left(x\right)=x^2-8$, find $ff\left(x\right)$.