$(\,2+\,y)\;(\,4\,x+\,1) = $   ?

$\,6\,\,x +\,3 +\,5\,\,x\,y +\,2\,\,y$ $\,8\,\,x +\,2 +\,4\,\,x\,y +\,\,y$ $\,4\,\,x\,y +\,2$ $\,13\,\,x^2\,y^2 +\,2$

$(\,2\,t+\,4)\;(\,3+\,t) = $   ?

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

$(\,4+\,y)\;(\,2\,x+\,3) = $   ?

$\,2\,\,x\,y +\,12$ $\,6\,\,x +\,7 +\,3\,\,x\,y +\,4\,\,y$ $\,8\,\,x +\,12 +\,2\,\,x\,y +\,3\,\,y$ $\,13\,\,x^2\,y^2 +\,12$

$(\,2+\,y)\;(\,5\,y+\,2) = $   ?

$\,5\,\,y^2 +\,12\,\,y +\,4$ $\,6\,\,y^2 +\,10\,\,y +\,4$ $\,5\,\,y^2 +\,4$ $\,17\,\,y +\,4$

$(\,3\,b\,-3)\;(\,a+\,4) = $   ?

$\,-3\,\,a\,b +\,12\,\,b \,-3\,\,a +\,12$ $\,3\,\,a\,b +\,12\,\,b \,-3\,\,a \,-12$ $\,3\,\,a\,b \,-12\,\,b +\,3\,\,a \,-12$ $\,3\,\,a\,b \,-12\,\,b \,-3\,\,a +\,12$

$(\,5+\,2\,a)\;(\,-3\,b\,-1) = $   ?

$\,15\,\,b \,-5 \,-6\,\,a\,b +\,2\,\,a$ $\,15\,\,b \,-5 +\,6\,\,a\,b \,-2\,\,a$ $\,-15\,\,b \,-5 \,-6\,\,a\,b \,-2\,\,a$ $\,-15\,\,b +\,5 +\,6\,\,a\,b \,-2\,\,a$

$(\,2+\,2\,t)\;(\,1\,-5\,t) = $   ?

$\,10\,\,t^2 \,-8\,\,t \,-2$ $\,-10\,\,t^2 \,-8\,\,t +\,2$ $\,-10\,\,t^2 +\,8\,\,t +\,2$ $\,-10\,\,t^2 +\,12\,\,t \,-2$

$(\,2\,b\,-5)\;(\,-4\,-\,a) = $   ?

$\,-8\,\,b +\,2\,\,a\,b +\,20 +\,5\,\,a$ $\,8\,\,b \,-2\,\,a\,b +\,20 \,-5\,\,a$ $\,-8\,\,b \,-2\,\,a\,b \,-20 +\,5\,\,a$ $\,-8\,\,b \,-2\,\,a\,b +\,20 +\,5\,\,a$

$(\,6+\,6\,b)\;(\,-\,b\,-5) = $   ?

$\,6\,\,b^2 +\,24\,\,b \,-30$ $\,6\,\,b^2 \,-24\,\,b \,-30$ $\,-6\,\,b^2 \,-24\,\,b +\,30$ $\,-6\,\,b^2 \,-36\,\,b \,-30$

$(\,y\,-2)\;(\,-2\,-6\,y) = $   ?

$\,-6\,\,y^2 \,-14\,\,y \,-4$ $\,-6\,\,y^2 +\,14\,\,y \,-4$ $\,6\,\,y^2 \,-14\,\,y +\,4$ $\,-6\,\,y^2 +\,10\,\,y +\,4$