Question

If the point $A(2,3)$ lies on the graph of the equation $5x+ay=19$, then find $a$.

Answer 1

Since $A(2,3)$ lies on $5x+ay=19$
It satisfies the given equation.
$\Rightarrow 5\times 2+a\times 3=19$
$\Rightarrow 10+3a=19$
$\Rightarrow 3a=9$
$\Rightarrow a=3$