#### Answer

$-7$

#### Work Step by Step

First, solving for x,
$3(x+3)=5(2x+6)$
$3x+9=10x+30$
$7x=-21$
$So,\,\,\,x=-3$
Second, solving for y,
$-2y-10=5y+18$
$7y=-28$
$So,\,\,\,y=-4$
Now, inserting values of x and y,
$x^{2}-(xy-y)=(-3)^{2}-((-3)(-4)-(-4))=9-(12+4)=-7$