Express the following linear equation in the form $ax + by + c = 0$ and indicate the values of $a, b$ and $c$ in each case:
$5x + 3y = 45$

The linear equation $2x - 5y = 7$ has:

State whether the following statement is true or false:
An equation in two variables has a unique solution.

One of the solutions of the linear equation $3x + 5y = 30$ is $\ldots \ldots . .$

If the temperature of a liquid can be measured in Kelvin units as $x^{\circ} K$ or in Fahrenheit units as $y^{\circ} F$,the relation between the two systems of measurement of temperature is given by the linear equation
$y = \frac{9}{5}(x - 273) + 32$
$(i)$ Find the temperature of the liquid in Fahrenheit if the temperature of the liquid is $313^{\circ} K$.
$(ii)$ If the temperature is $158^{\circ} F$,then find the temperature in Kelvin.

Write $5 x-3 y=15$ in the standard form of a linear equation in two variables.