From Förberedande kurs i matematik 1

The point of intersection is that point which satisfies the equations of both lines

\displaystyle 4x+5y+6=0\qquad\text{and}\qquad x=0\,\textrm{.}

Substituting \displaystyle x=0 into \displaystyle 4x+5y+6=0 gives

\displaystyle 4\cdot 0+5y+6=0\quad\Leftrightarrow\quad y=-\frac{6}{5}\,\textrm{.}

This gives the point of intersection as \displaystyle \bigl(0,-\tfrac{6}{5}\bigr).