Question 1166890
{{{9x^2+72x+16y^2-96y=-144}}}
{{{9(x^2+8x)+16(y^2-6y)=-144}}}
{{{9(x^2+8x+16)+16(y^2-6y+9)=-144+9*16+16*9}}}, completing the squares
{{{9(x+4)^2+16(y-3)^2=144}}}

{{{(9/144)(x+4)^2+(16/144)(y-3)^2=1}}}

{{{highlight((x+4)^2/4^2+(y-3)^2/3^2=1)}}}