$(\,1+\,3\,y)\;(\,5+\,x) = $   ?

$\,19\,\,x^2\,y^2 +\,5$ $\,5 +\,\,x +\,15\,\,y +\,3\,\,x\,y$ $\,6 +\,2\,\,x +\,8\,\,y +\,4\,\,x\,y$ $\,3\,\,x\,y +\,5$

$(\,4+\,2\,x)\;(\,3+\,x) = $   ?

$\,12\,\,x +\,12$ $\,2\,\,x^2 +\,10\,\,x +\,12$ $\,2\,\,x^2 +\,12$ $\,3\,\,x^2 +\,10\,\,x +\,7$

$(\,6+\,6\,x)\;(\,y+\,5) = $   ?

$\,6\,\,y +\,30 +\,6\,\,x\,y +\,30\,\,x$ $\,42\,\,x^2\,y^2 +\,30$ $\,6\,\,x\,y +\,30$ $\,7\,\,y +\,11 +\,7\,\,x\,y +\,11\,\,x$

$(\,5\,x+\,3)\;(\,2\,x+\,1) = $   ?

$\,7\,\,x^2 +\,11\,\,x +\,4$ $\,21\,\,x +\,3$ $\,10\,\,x^2 +\,3$ $\,10\,\,x^2 +\,11\,\,x +\,3$

$(\,t\,-4)\;(\,4+\,5\,x) = $   ?

$\,4\,\,t +\,5\,\,t\,x +\,16 \,-20\,\,x$ $\,4\,\,t +\,5\,\,t\,x \,-16 \,-20\,\,x$ $\,-4\,\,t \,-5\,\,t\,x \,-16 \,-20\,\,x$ $\,-4\,\,t +\,5\,\,t\,x \,-16 +\,20\,\,x$

$(\,3+\,3\,a)\;(\,-6\,-\,b) = $   ?

$\,-18 +\,3\,\,b +\,18\,\,a \,-3\,\,a\,b$ $\,-18 \,-3\,\,b \,-18\,\,a \,-3\,\,a\,b$ $\,-18 \,-3\,\,b \,-18\,\,a +\,3\,\,a\,b$ $\,-18 \,-3\,\,b +\,18\,\,a +\,3\,\,a\,b$

$(\,3\,-\,t)\;(\,4+\,6\,t) = $   ?

$\,6\,\,t^2 +\,22\,\,t +\,12$ $\,-6\,\,t^2 +\,22\,\,t +\,12$ $\,-6\,\,t^2 +\,14\,\,t +\,12$ $\,6\,\,t^2 +\,14\,\,t \,-12$

$(\,4\,y\,-6)\;(\,-5\,-\,x) = $   ?

$\,20\,\,y +\,4\,\,x\,y +\,30 +\,6\,\,x$ $\,-20\,\,y +\,4\,\,x\,y +\,30 +\,6\,\,x$ $\,-20\,\,y \,-4\,\,x\,y +\,30 +\,6\,\,x$ $\,-20\,\,y +\,4\,\,x\,y \,-30 +\,6\,\,x$

$(\,5+\,b)\;(\,-6\,-2\,b) = $   ?

$\,-2\,\,b^2 \,-4\,\,b +\,30$ $\,-2\,\,b^2 \,-16\,\,b \,-30$ $\,-2\,\,b^2 +\,4\,\,b \,-30$ $\,2\,\,b^2 \,-16\,\,b \,-30$

$(\,4\,-2\,t)\;(\,-\,t\,-4) = $   ?

$\,2\,\,t^2 +\,4\,\,t \,-16$ $\,2\,\,t^2 \,-4\,\,t \,-16$ $\,2\,\,t^2 \,-12\,\,t \,-16$ $\,2\,\,t^2 \,-12\,\,t +\,16$