TeX source:
\begin{array}{rclcl} (6+8y)^2 &=& 16(4y+3)\left(y+\dfrac{3}{4}\right) \cr\cr 36+96y+64y^2 &=& 16(4y+3)\left(y+\dfrac{3}{4}\right) & \vert & :4 \cr\cr 9+24y+16y^2 &=& 16 \left(y+\dfrac{3}{4}\right)\left(y+\dfrac{3}{4}\right) \cr\cr 9+24y+16y^2 &=& 16\left(y^2+\dfrac{3}{2}y+\dfrac{9}{16}\right) \cr\cr 9+24y+16y^2 &=& 16y^2+24y+9 &\vert& -16y^2-24y-9 \cr\cr 0 &=& 0 \cr \cr \mathbb{L} &=& \mathbb{R} \end{array}