$(\,1+\,a)\;(\,4+\,b) = $   ?

$\,5 +\,2\,\,b +\,5\,\,a +\,2\,\,a\,b$ $\,4 +\,\,b +\,4\,\,a +\,\,a\,b$ $\,\,a\,b +\,4$ $\,6\,\,a^2\,b^2 +\,4$

$(\,y+\,6)\;(\,4+\,y) = $   ?

$\,2\,\,y^2 +\,12\,\,y +\,10$ $\,\,y^2 +\,24$ $\,\,y^2 +\,10\,\,y +\,24$ $\,11\,\,y +\,24$

$(\,4+\,6\,x)\;(\,y+\,1) = $   ?

$\,5\,\,y +\,5 +\,7\,\,x\,y +\,7\,\,x$ $\,6\,\,x\,y +\,4$ $\,16\,\,x^2\,y^2 +\,4$ $\,4\,\,y +\,4 +\,6\,\,x\,y +\,6\,\,x$

$(\,5+\,2\,t)\;(\,4\,t+\,3) = $   ?

$\,34\,\,t +\,15$ $\,8\,\,t^2 +\,15$ $\,6\,\,t^2 +\,14\,\,t +\,8$ $\,8\,\,t^2 +\,26\,\,t +\,15$

$(\,x+\,3)\;(\,-2+\,5\,y) = $   ?

$\,-2\,\,x +\,5\,\,x\,y \,-6 +\,15\,\,y$ $\,-2\,\,x \,-5\,\,x\,y \,-6 +\,15\,\,y$ $\,2\,\,x \,-5\,\,x\,y \,-6 +\,15\,\,y$ $\,-2\,\,x +\,5\,\,x\,y +\,6 +\,15\,\,y$

$(\,6\,a+\,6)\;(\,-5\,-\,b) = $   ?

$\,30\,\,a +\,6\,\,a\,b \,-30 \,-6\,\,b$ $\,-30\,\,a \,-6\,\,a\,b \,-30 \,-6\,\,b$ $\,30\,\,a \,-6\,\,a\,b \,-30 \,-6\,\,b$ $\,-30\,\,a +\,6\,\,a\,b \,-30 +\,6\,\,b$

$(\,6\,t\,-2)\;(\,4\,t+\,6) = $   ?

$\,-24\,\,t^2 +\,28\,\,t +\,12$ $\,24\,\,t^2 +\,28\,\,t \,-12$ $\,24\,\,t^2 +\,44\,\,t +\,12$ $\,-24\,\,t^2 +\,28\,\,t \,-12$

$(\,2\,x\,-4)\;(\,-6\,-3\,y) = $   ?

$\,-12\,\,x \,-6\,\,x\,y +\,24 +\,12\,\,y$ $\,-12\,\,x +\,6\,\,x\,y +\,24 \,-12\,\,y$ $\,-12\,\,x +\,6\,\,x\,y +\,24 +\,12\,\,y$ $\,12\,\,x +\,6\,\,x\,y +\,24 +\,12\,\,y$

$(\,5\,-3\,y)\;(\,4\,y\,-1) = $   ?

$\,-12\,\,y^2 \,-17\,\,y \,-5$ $\,12\,\,y^2 +\,23\,\,y \,-5$ $\,-12\,\,y^2 +\,17\,\,y \,-5$ $\,-12\,\,y^2 +\,23\,\,y \,-5$

$(\,5\,t\,-4)\;(\,-6\,-5\,t) = $   ?

$\,-25\,\,t^2 \,-10\,\,t \,-24$ $\,-25\,\,t^2 \,-10\,\,t +\,24$ $\,-25\,\,t^2 +\,10\,\,t +\,24$ $\,25\,\,t^2 \,-50\,\,t +\,24$