Question 317511
The rectangle's area is,
{{{A1=L*W=4y(y-3)=4y^2-12}}}
The area of the square is,
{{{A2=s^2=(y-7)^2=y^2-14y+49}}}
The remaining area is,
{{{A=A1-A2=4y^2-12-(y^2-14y+49)}}}
{{{highlight(A=3y^2+14y-61)}}}